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in this study, we calculate the sensitivity reach on the vector leptoquark (lq) u1 at the experiments proposed in the forward physics facility (fpf), including faser ν , faser ν 2 , flare (10 tons), and flare (100 tons) using the neutrino-nucleon scattering (ν n →ν n' and ν n →l n'). we cover a wide mass range of 10-3 gev ≤mlq≤104 gev . the new result shows that the flare (100 tons) offers the best sensitivity to the lq model. the sensitivity curves for all the experiments follow a similar pattern with weakened sensitivities with the increment of the lq mass. we combine the sensitivities obtained from the neutral- and charged-current interactions of the neutrinos. | leptoquark search at the forward physics facility |
a search for the production of pairs of heavy majorana neutrinos (nℓ) from the decays of z' bosons is performed using the cms detector at the lhc. the data were collected in proton-proton collisions at a center-of-mass energy of √{s } = 13 tev, with an integrated luminosity of 138 fb−1. the signature for the search is an excess in the invariant mass distribution of the final-state objects, two same-flavor leptons (e or μ) and at least two jets. no significant excess of events beyond the expected background is observed. upper limits at 95% confidence level are set on the product of the z' production cross section and its branching fraction to a pair of nℓ, as functions of nℓ and z' boson masses (mnℓ and mz', respectively) for mz' from 0.4 to 4.6 tev and mn ℓ from 0.1 tev to mz'/2. in the theoretical framework of a left-right symmetric model, exclusion bounds in the mn ℓ-mz' plane are presented in both the electron and muon channels. the observed upper limit on mz' reaches up to 4.42 tev. these are the most restrictive limits to date on the mass of nℓ as a function of the z' boson mass. | search for z' bosons decaying to pairs of heavy majorana neutrinos in proton-proton collisions at √{s } = 13 tev |
incompleteness in current knowledge of neutrino interactions with nuclear matter imposes a primary limitation in searches for leptonic c p violation carried out at long-baseline neutrino experiments. in this paper, we present a new computation that elevates the theoretical accuracy to next-to-next-to-leading order in qcd for charged-current deeply inelastic scattering processes relevant for ongoing and future neutrino programs. mass-dependent quark contributions are consistently included across a wide range of momentum transfers in the simplified-acot-χ general-mass scheme. when appropriate, we further include next-to-next-to-next-to-leading order corrections in the zero-mass scheme. we show theoretical predictions for several experiments with neutrinos over a wide range of energies and at the upcoming electron-ion collider. our prediction reduces perturbative uncertainties to ∼1 %, sufficient for the high-precision objectives of future charged-current deeply inelastic scattering measurements, and provides important theoretical inputs to experimental studies of leptonic mixing and c p violations. | general heavy-flavor mass scheme for charged-current dis at nnlo and beyond |
neutrino-nucleus coherent scattering measurements by the coherent collaboration provide us with a unique capability to test various beyond the standard model scenarios. in this work, we constrain scalar leptoquarks (lqs) using the coherent data. lqs arise in many extensions of the standard model (sm). generally, the mass of the lqs is assumed to be very high to avoid the bounds from proton decay. however, there are low-scale lq models which prohibit proton decay by construction. we consider two electroweak doublet scalar lq models with hypercharge y =1 /6 , and y =7 /6 and provide the bounds in the plane of the yukawa coupling and the mass of lq. we also compare the bounds on lqs coming from various other experiments and find that the coherent one covers a wide range of lq masses from mev to tev and in certain regions the constraints are competitive with the others. | constraining scalar leptoquarks using coherent data |
we explore the prospects of constraining general non standard interactions involving light mediators through elastic neutrino-electron scattering events at the dune near detector (nd). we furthermore consider the special cases of light vector mediators in motivated models such as u(1)b−l, u (1)lμ−lτ, e6 and left-right symmetry. the present analysis is based on detailed monte carlo simulations of the expected dune-nd signal taking into account detector resolution effects, realistic backgrounds as well as on-axis and off-axis neutrino spectra. we show that the high intensity neutrino beam available at fermilab can place competitive constraints surpassing those of low-energy neutrino searches and direct detection dark matter experiments. | probing generalized neutrino interactions with the dune near detector |
the couplings of the higgs boson (h) with massive gauge bosons of weak interaction (v = w, z), can be probed in single higgs boson production at the proposed future large hadron-electron collider (lhec). in the collision of an electron with a pro- ton, single higgs production takes place via so-called charged-current (e−p → νehj) and neutral-current (e−p → e−hj) processes. we explore the potential of the azimuthal angle correlation between the forward jet and scattered neutrino or electron in probing the non-standard hvv couplings at the collider center-of-mass energy of √{s } ≈ 1.3 tev. we choose the most general modifications (of cp-even and cp-odd nature) to these couplings due to new physics effects beyond the standard model. we derive exclusion limits on new physics parameters of hv v couplings as a function of integrated luminosity at 95% c.l. using the azimuthal angular correlations in charged- and neutral-current processes. we find that using 1000 fb−1 data, the standard model-like new physics parameters in hww and hzz couplings can be constrained with accuracies of 4% and 15%, respectively. the least constrained cp-even parameters of hww coupling can be as large as 0.04, while those of hzz coupling can have values around 0.31. allowed values of cp-odd parameters in hww and hzz couplings are found to be around 0.14 and 0.34, respectively. we also study changes in the allowed values of non-trivial new physics parameters in the presence of other parameters. | probing non-standard hvv (v = w, z) couplings in single higgs production at future electron-proton collider |
the neut intranuclear cascade model is described and fit to a large body of π± -nucleus scattering data. methods are developed to deal with deficiencies in the available historical data, and robust uncertainty estimates are produced. the results are compared to a variety of simulation packages and the data. this work provides a method for tuning final state interaction models, which are of particular interest to neutrino experiments that operate in the few-gev energy region, and provides results which can be used directly by the t2k and super-kamiokande collaborations, for whom neut is the primary simulation package. | using world π±-nucleus scattering data to constrain an intranuclear cascade model |
we calculate the nucleon axial form factor up to the leading one-loop order in a covariant chiral effective field theory with the δ (1232 ) resonance as an explicit degree of freedom. we fit the axial form factor to the latest lattice qcd data and pin down the relevant low-energy constants. the lattice qcd data, for various pion masses below 400 mev, can be well described up to a momentum transfer of ∼0.6 gev . the δ (1232 ) loops contribute significantly to this agreement. furthermore, we extract the axial charge and radius based on the fitted values of the low-energy constants. the results are ga=1.237 (74 ) and ⟨ra2⟩=0.263 (38 ) fm2 . the obtained coupling ga is consistent with the experimental value if the uncertainty is taken into account. the axial radius is below but in agreement with the recent extraction from neutrino quasielastic scattering data on deuterium, which has large error bars. up to our current working accuracy, ra is predicted only at leading order, i.e., the one-loop level. a more precise determination might need terms of o (p5). | extraction of nucleon axial charge and radius from lattice qcd results using baryon chiral perturbation theory |
dual-phase xenon tpc detectors are a highly scalable and widely used technology to search for low-energy nuclear recoil signals from wimp dark matter or coherent nuclear scattering of $\sim$mev neutrinos. such experiments expect to measure o(kev) ionization or scintillation signals from such sources. however, at $\sim1\,$kev and below, the signal calibrations in liquid xenon carry large uncertainties that directly impact the assumed sensitivity of existing and future experiments. in this work, we report a new measurement of the ionization yield of nuclear recoil signals in liquid xenon down to 0.3$\,$kev$\,\,$-- the lowest energy calibration reported to date -- at which energy the average event produces just 1.1~ionized~electrons. between 2 and 6$\,$kev, our measurements agree with existing measurements, but significantly improve the precision. at lower energies, we observe a decreasing trend that deviates from simple extrapolations of existing data. we also study the dependence of ionization yield on the applied drift field in liquid xenon between 220v/cm and 6240v/cm, allowing these measurements to apply to a broad range of current and proposed experiments with different operating parameters. | measurement of the ionization yield from nuclear recoils in liquid xenon between 0.3 -- 6 kev with single-ionization-electron sensitivity |
a beam dump experiment can be seamlessly added to the proposed inter- national linear collider (ilc) program because the high energy electron beam should be dumped after the collision point. the ilc beam dump experiment will provide an excellent opportunity to search for new long-lived particles. since many of them can be produced by a rare decay of standard model particles, we evaluate spectra of the mesons and τ lepton at the decay based on the phits and pythia8 simulations. as a motivated physics case, we study the projected sensitivity of heavy neutral leptons at the ilc beam dump experiment. the heavy neutral leptons can also be produced via deep inelastic scattering and z boson decay at the ilc main detector, which we include in the projection. with the multi-track signal, the reach would be greatly extended in mass and coupling, even compared with the other proposed searches. | first evaluation of meson and τ lepton spectra and search for heavy neutral leptons at ilc beam dump |
we point out that the ldmx (light dark matter experiment) detector design, conceived to search for sub-gev dark matter, will also have very advantageous characteristics to pursue electron-nucleus scattering measurements of direct relevance to the neutrino program at dune and elsewhere. these characteristics include a 4-gev electron beam, a precision tracker, electromagnetic and hadronic calorimeters with near 2 π azimuthal acceptance from the forward beam axis out to ∼40 ° angle, and low reconstruction energy threshold. ldmx thus could provide (semi)exclusive cross section measurements, with detailed information about final-state electrons, pions, protons, and neutrons. we compare the predictions of two widely used neutrino generators (uc(genie), uc(g)iuc(buu)) in the ldmx region of acceptance to illustrate the large modeling discrepancies in electron-nucleus interactions at dune-like kinematics. we argue that discriminating between these predictions is well within the capabilities of the ldmx detector. | lepton-nucleus cross section measurements for dune with the ldmx detector |
we report the first measurement of monoenergetic muon neutrino charged current interactions. miniboone has isolated 236 mev muon neutrino events originating from charged kaon decay at rest (k+→μ+νμ) at the numi beamline absorber. these signal νμ -carbon events are distinguished from primarily pion decay in flight νμ and ν¯μ backgrounds produced at the target station and decay pipe using their arrival time and reconstructed muon energy. the significance of the signal observation is at the 3.9 σ level. the muon kinetic energy, neutrino-nucleus energy transfer (ω =eν-eμ), and total cross section for these events are extracted. this result is the first known-energy, weak-interaction-only probe of the nucleus to yield a measurement of ω using neutrinos, a quantity thus far only accessible through electron scattering. | first measurement of monoenergetic muon neutrino charged current interactions |
the unitarization of the longitudinal vector boson scattering (vbs) cross section by the higgs boson is a fundamental prediction of the standard model which has not been experimentally verified. one of the most promising ways to measure vbs uses events containing two leptonically decaying same-electric-charge w bosons produced in association with two jets. however, the angular distributions of the leptons in the w boson rest frame, which are commonly used to fit polarization fractions, are not readily available in this process due to the presence of two neutrinos in the final state. in this paper we present a method to alleviate this problem by using a deep machine learning technique to recover these angular distributions from measurable event kinematics and demonstrate how the longitudinal-longitudinal scattering fraction could be studied. we show that this method doubles the expected sensitivity when compared to previous proposals. | determination of the w w polarization fractions in p p →w±w±j j using a deep machine learning technique |
the couplings between the neutrinos and exotic fermion can be probed in both neutrino scattering experiments and dark matter direct detection experiments. we present a detailed analysis of the general neutrino interactions with an exotic fermion and electrons at neutrino-electron scattering experiments. we obtain the constraints on the coupling coefficients of the scalar, pseudoscalar, vector, axialvector, tensor and electromagnetic dipole interactions from the charm-ii, texono and borexino experiments. for the flavor-universal interactions, we find that the borexino experiment sets the strongest bounds in the low mass region for the electromagnetic dipole interactions, and the charm-ii experiment dominates the bounds for other scenarios. if the interactions are flavor dependent, the bounds from the charm-ii or texono experiment can be avoided, and there are correlations between the flavored coupling coefficients for the borexino experiment. we also discuss the detection of sub-mev dm absorbed by bound electron targets and illustrate that the vector coefficients preferred by xenon1t data are allowed by the neutrino-electron scattering experiments. | constraints on general neutrino interactions with exotic fermion from neutrino-electron scattering experiments |
we propose a model with two higgs doublets and several su(2) scalar singlets with a global non-abelian flavor symmetry q6×z2. this discrete group accounts for the observed pattern of fermion masses and mixing angles after spontaneous symmetry breaking. in this scenario only the third generation of fermions get their masses as in the standard model (sm). the masses of the remaining fermions are generated through a seesaw-like mechanism. to that end, the matter content of the model is enlarged by introducing electrically charged vector-like fermions (vlfs), right handed majorana neutrinos and several sm scalar singlets. here we study the processes involving vlfs that are within the reach of the large hadron collider (lhc). we perform collider studies for vector-like leptons (vlls) and vector-like quarks (vlqs), focusing on double production channels for both cases, while for vlls single production topologies are also included. utilizing genetic algorithms for neural network optimization, we determine the statistical significance for a hypothetical discovery at future lhc runs. in particular, we show that we can not safely exclude vlls for masses greater than 200 gev. for vlq's in our model, we show that we can probe their masses up to 3.8 tev, if we take only into account the high-luminosity phase of the lhc. considering run-iii luminosities, we can also exclude vlqs for masses up to 3.4 tev. we also show how the model with predicted vll masses accommodates the muon anomalous magnetic moment. | collider signatures of vector-like fermions from a flavor symmetric model |
we report constraints on nonstandard neutrino interactions (nsi) from the observation of atmospheric neutrinos with icecube, limiting all individual coupling strengths from a single dataset. furthermore, icecube is the first experiment to constrain flavor-violating and nonuniversal couplings simultaneously. hypothetical nsi are generically expected to arise due to the exchange of a new heavy mediator particle. neutrinos propagating in matter scatter off fermions in the forward direction with negligible momentum transfer. hence the study of the matter effect on neutrinos propagating in the earth is sensitive to nsi independently of the energy scale of new physics. we present constraints on nsi obtained with an all-flavor event sample of atmospheric neutrinos based on three years of icecube deepcore data. the analysis uses neutrinos arriving from all directions, with reconstructed energies between 5.6 gev and 100 gev. we report constraints on the individual nsi coupling strengths considered singly, allowing for complex phases in the case of flavor-violating couplings. this demonstrates that icecube is sensitive to the full nsi flavor structure at a level competitive with limits from the global analysis of all other experiments. in addition, we investigate a generalized matter potential, whose overall scale and flavor structure are also constrained. | all-flavor constraints on nonstandard neutrino interactions and generalized matter potential with three years of icecube deepcore data |
we investigate the effects of the transitional magnetic dipole type interactions of the active-to-heavy-neutrino associated with a new neutral gauge boson z' on neutrino-nucleon scattering at the forward search experiment-ν (faserν ). we consider the neutral-current neutrino-nucleon scattering (ν a →n a' , where a' denotes the disintegrated nuclei) as the production mechanism of the heavy neutrino n at faserν and estimate the sensitivity reach on the magnetic-type dipole coupling ωνα for a range of heavy neutrino mass (1 gev<mn<70 gev ). in this study, we consider three benchmark models, in which the heavy neutrino is coupled to le, lμ or lτ doublet, respectively. | constraining the transitional magnetic dipole moment interaction between active and heavy neutrinos with the z' at faserν |
we present an overview of recent progress toward the ricochet coherent elastic neutrino nucleus scattering (ceν ns) experiment. the ill research reactor in grenoble, france has been selected as the experiment site, after in situ studies of vibration and particle backgrounds. we present background rate estimates specific to that site, along with descriptions of the planned cryocube and q-array detector payloads. | ricochet progress and status |
we revisit the sensitivity to non-resonant, heavy majorana neutrinos $n$ in same-sign $w^\pm w^\pm$ scattering at the $\sqrt{s}=13$ tev lhc and its high-luminosity upgrade. as a benchmark scenario, we work in the context of the phenomenological type i seesaw model, relying on a simulation up to next-to-leading order in qcd with parton shower matching. after extensively studying the phenomenology of the $pp\to\mu^\pm\mu^\pm j j$ process at the amplitude and differential levels, we design a simple collider analysis with remarkable signal-background separation power. at 95\% confidence level we find that the squared muon-heavy neutrino mixing element $\vert v_{\mu n} \vert^{2}$ can be probed down to about $0.06-0.3 ~ (0.03-0.1)$ for $m_n = 1-10~{\rm tev}$ with $\mathcal{l}=300$ fb$^{-1}~(3$ ab$^{-1})$. for heavier masses of $m_n = 20~{\rm tev}$, we report sensitivity for $\vert v_{\mu n} \vert^{2}\gtrsim 0.5~(0.3)$. the $w^\pm w^\pm$ scattering channel can greatly extend the mass range covered by current lhc searches for heavy majorana neutrinos and particularly adds invaluable sensitivity above a few hundred gev. we comment on areas where the analysis can be improved as well as on the applicability to other tests of neutrino mass models. | majorana neutrinos in same-sign $w^\\pm w^\\pm$ scattering at the lhc: breaking the tev barrier |
we report the first measurement of the flux-averaged cross section for charged current coherent π+ production on carbon for neutrino energies less than 1.5 gev, and with a restriction on the final state phase space volume in the t2k near detector, nd280. comparisons are made with predictions from the rein-sehgal coherent production model and the model by alvarez-ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction monte carlo event generator. we observe a clear event excess above background, disagreeing with the null results reported by k2k and sciboone in a similar neutrino energy region. the measured flux-averaged cross sections are below those predicted by both the rein-sehgal and alvarez-ruso et al. models. | measurement of coherent π+ production in low energy neutrino-carbon scattering |
coherent elastic neutrino-nucleus scattering and low-mass dark matter detectors rely crucially on the understanding of their response to nuclear recoils. we report the first observation of a nuclear recoil peak at around 112 ev induced by neutron capture. the measurement was performed with a cawo4 cryogenic detector from the nucleus experiment exposed to a cf 252 source placed in a compact moderator. we identify the expected peak structure from the single-γ de-excitation of w 183 with 3 σ and its origin by neutron capture with 6 σ significance. this result demonstrates a new method for precise, in situ, and nonintrusive calibration of low-threshold experiments. | observation of a nuclear recoil peak at the 100 ev scale induced by neutron capture |
leptoquarks are theorized particles of either scalar or vector nature that couple simultaneously to quarks and leptons. motivated by recent measurements of coherent elastic neutrino-nucleus scattering, we consider the impact of scalar leptoquarks coupling to neutrinos on a few complementary processes, from low energy to colliders. in particular, we set competitive constraints on the typical mass and coupling of scalar leptoquarks by analyzing recent coherent data. we compare these constraints with bounds from atomic parity violation experiments, deep inelastic neutrino-nucleon scattering and lhc data. our results highlight a strong complementarity between different facilities and demonstrate the compelling power of coherent elastic neutrino-nucleus scattering experiments to probe leptoquark masses in the mev-gev range. finally, we also present prospects for improving current bounds with future upgrades of the coherent detectors and the planned european spallation source. | a neutrino window to scalar leptoquarks: from low energy to colliders |
coherent elastic neutrino-nucleus scattering (cevns) is calculated to be the dominant neutrino scattering channel for neutrinos of energy eν<100 mev . we report a limit for this process from data collected in an engineering run of the 29 kg cenns-10 liquid argon detector located 27.5 m from the pion decay-at-rest neutrino source at the oak ridge national laboratory spallation neutron source (sns) with 4.2 ×1022 protons on target. the dataset provided constraints on beam-related backgrounds critical for future measurements and yielded <7.4 candidate cevns events which implies a cross section for the process, averaged over the sns pion decay-at-rest flux, of <3.4 ×10-39 cm2 , a limit within twice the standard model prediction. this is the first limit on cevns from an argon nucleus and confirms the earlier csi[na] nonstandard neutrino interaction constraints from the collaboration. this run demonstrated the feasibility of the ongoing experimental effort to detect cevns with liquid argon. | first constraint on coherent elastic neutrino-nucleus scattering in argon |
the quest for new physics beyond the standard model is boosted by the recently observed deviation in the anomalous magnetic moments of muon and electron from their respective theoretical prediction. in the present work, we have proposed a suitable extension of the minimal $l_{\mu}-l_{\tau}$ model to address these two experimental results as the minimal model is unable to provide any realistic solution. in our model, a new yukawa interaction involving first generation of leptons, a singlet vector like fermion ($\chi^{\pm}$) and a scalar (either an su(2)$_{l}$ doublet $\phi^\prime_2$ or a complex singlet $\phi^\prime_4$) provides the additional one loop contribution to $a_{e}$ only on top of the usual contribution coming from the $l_{\mu}-l_{\tau}$ gauge boson ($z_{\mu\tau}$) to both electron and muon. the judicious choice of $l_{\mu}-l_{\tau}$ charges to these new fields results in a strongly interacting scalar dark matter in $\mathcal{o}({\rm mev})$ range after taking into account the bounds from relic density, unitarity and self interaction. the freeze-out dynamics of dark matter is greatly influenced by $3\rightarrow2$ scatterings while the kinetic equilibrium with the sm bath is ensured by $2\rightarrow2$ scatterings with neutrinos where $z_{\mu\tau}$ plays a pivotal role. the detection of dark matter is possible directly through scatterings with nuclei mediated by the sm $z$ bosons. moreover, our proposed model can also be tested in the upcoming $e^+e^-$ colliders by searching opposite sign di-electron and missing energy signal i.e. $e^{+} e^{-} \rightarrow \chi^{+} \chi^{-} \rightarrow e^{+} e^{-} \cancel{e}_t$ at the final state. | $(g-2)_{e,\\,\\mu}$ and strongly interacting dark matter with collider implications |
we explore the sensitivity of the deep underground neutrino experiment (dune) near detector and the proposed dune-prism movable near detector to sub-gev dark matter, specifically scalar dark matter coupled to the standard model via a sub-gev dark photon. we consider dark matter produced in the dune target that travels to the detector and scatters off electrons. by combining searches for dark matter at many off-axis positions with dune-prism, sensitivity to this scenario can be much stronger than when performing a measurement at one on-axis position. | hunting on- and off-axis for light dark matter with dune-prism |
one of the most puzzling questions in neutrino physics is the origin of the excess at 5 mev in the reactor antineutrino spectrum. in this paper, we explore the excess via the reaction 13c (ν ¯ ,ν¯ 'n )12c (*) in organic scintillator detectors. the deexcitation of 12c (*) yields a prompt 4.4 mev photon, while the thermalization of the product neutron causes proton recoils, which in turn yield an additional prompt energy contribution with finite width. together, these effects can mimic an inverse beta decay event with around 5 mev energy. we consider several nonstandard neutrino interactions to produce such a process and find that the parameter space preferred by daya bay is disfavored by measurements of neutrino-induced deuteron disintegration and coherent elastic neutrino-nucleus scattering. while nonminimal particle physics scenarios may be viable, a nuclear physics solution to this anomaly appears more appealing. | particle physics origin of the 5 mev bump in the reactor antineutrino spectrum? |
one of the important goals of the proposed future e+e- collider experiments is the search for dark matter particles using different experimental approaches. the most general search approach is based on the mono-photon signature, which is expected when production of the invisible final state is accompanied by a hard photon from initial state radiation. analysis of the energy spectrum and angular distributions of those photons can shed light on the nature of dark matter and its interactions. therefore, it is crucial to be able to simulate the signal and background samples in a uniform framework, to avoid possible systematic biases. the whizard program is a flexible tool, which is widely used by e+e- collaborations for simulation of many different "new physics" scenarios. we propose the procedure of merging the matrix element calculations with the lepton isr structure function implemented in whizard. it allows us to reliably simulate the mono-photon events, including the two main standard model background processes: radiative neutrino pair production and radiative bhabha scattering. we demonstrate that cross sections and kinematic distributions of mono-photon in neutrino pair-production events agree with corresponding predictions of the kk mc, a monte carlo generator providing perturbative predictions for sm and qed processes, which has been widely used in the analysis of lep data. | simulating hard photon production with whizard |
the connie experiment uses fully depleted, high resistivity ccds as particle detectors in an attempt to measure for the first time the coherent neutrino-nucleus elastic scattering of antineutrinos from a nuclear reactor with silicon nuclei. this talk, given at the xv mexican workshop on particles and fields (mwpf), discussed the potential of connie to perform this measurement, the installation progress at the angra dos reis nuclear power plant, as well as the plans for future upgrades. | the connie experiment |
a search for a heavy right-handed w boson (wr) decaying to a heavy right-handed neutrino and a charged lepton in events with two same-flavor leptons (e or μ) and two jets, is presented. the analysis is based on proton-proton collision data, collected by the cms collaboration at the lhc in 2016 and corresponding to an integrated luminosity of 35.9 fb-1. no significant excess above the standard model expectation is seen in the invariant mass distribution of the dilepton plus dijet system. assuming that couplings are identical to those of the standard model, and that only one heavy neutrino flavor nr contributes significantly to the wr decay width, the region in the two-dimensional ({m}_{{w}r},{m}_{{n}r}) mass plane excluded at 95% confidence level extends to approximately {m}_{{w}r}=4.4 tev and covers a large range of right-handed neutrino masses below the wr boson mass. this analysis provides the most stringent limits on the wr mass to date. [figure not available: see fulltext.] | search for a heavy right-handed w boson and a heavy neutrino in events with two same-flavor leptons and two jets at √{s}=13 tev |
a thorough account of electromagnetic interactions of massive neutrinos in the theoretical formulation of low-energy elastic neutrino-electron scattering is given. the formalism of neutrino charge, magnetic, electric, and anapole form factors defined as matrices in the mass basis is employed under the assumption of three-neutrino mixing. the flavor change of neutrinos traveling from the source to the detector is taken into account and the role of the source-detector distance is inspected. the effects of neutrino flavor-transition millicharges and charge radii in the scattering experiments are pointed out. | electromagnetic properties of massive neutrinos in low-energy elastic neutrino-electron scattering |
current and future electron and neutrino scattering experiments will be greatly aided by a better understanding of the role played by short-range correlations in nuclei. two-body physics, including nucleon-nucleon correlations and two-body electroweak currents, is required to explain the body of experimental data for both static and dynamical nuclear properties. in this work, we focus on examining nucleon-nucleon correlations from a chiral effective field theory perspective and provide a comprehensive set of new variational monte carlo calculations of one- and two-body densities and momentum distributions based on the norfolk many-body nuclear hamiltonians for a ≤12 systems. online access to detailed tables and figures is available. | densities and momentum distributions in a ≤12 nuclei from chiral effective field theory interactions |
we discuss a technique for measuring a charged particle's momentum by means of multiple coulomb scattering (mcs) in the microboone liquid argon time projection chamber (lartpc). this method does not require the full particle ionization track to be contained inside of the detector volume as other track momentum reconstruction methods do (range-based momentum reconstruction and calorimetric momentum reconstruction). we motivate use of this technique, describe a tuning of the underlying phenomenological formula, quantify its performance on fully contained beam-neutrino-induced muon tracks both in simulation and in data, and quantify its performance on exiting muon tracks in simulation. using simulation, we have shown that the standard highland formula should be re-tuned specifically for scattering in liquid argon, which significantly improves the bias and resolution of the momentum measurement. with the tuned formula, we find agreement between data and simulation for contained tracks, with a small bias in the momentum reconstruction and with resolutions that vary as a function of track length, improving from about 10% for the shortest (one meter long) tracks to 5% for longer (several meter) tracks. for simulated exiting muons with at least one meter of track contained, we find a similarly small bias, and a resolution which is less than 15% for muons with momentum below 2 gev/c. above 2 gev/c, results are given as a first estimate of the mcs momentum measurement capabilities of microboone for high momentum exiting tracks. | determination of muon momentum in the microboone lartpc using an improved model of multiple coulomb scattering |
the form factors of the nucleon provide key information on nucleon properties. when confronted with precisely measured observables from experiments, they serve as benchmark quantities for lattice calculations. on the other hand lattice determinations may serve as vital theory input for the interpretation of experiments, e.g. in neutrino-nucleus scattering. i review recent progress in the calculation of nucleon form factors on the lattice and its relevance to future experiments. | recent progress on nucleon form factors |
we consider the light z' explanation of the muon g − 2 anomaly. even if such a z' has no tree-level coupling to electrons, in general one will be induced at loop-level. we show that future beam dump experiments are powerful enough to place stringent constraints on—or discover—a z' with loop-suppressed couplings to electrons. such bounds are avoided only if the z' has a large interaction with neutrinos, in which case the scenario will be bounded by ongoing neutrino scattering experiments. the complementarity between beam dump and neutrino scattering experiments therefore indicates that there are good prospects of probing a large part of the z' parameter space in the near future. | probing the muon g − 2 with future beam dump experiments |
large liquid argon detectors have become widely used in low rate experiments, including dark matter and neutrino research. however, the optical properties of liquid argon are not well understood at the large scales relevant for current and near-future detectors. the index of refraction of liquid argon at the scintillation wavelength has not been measured, and current rayleigh scattering length calculations disagree with measurements. furthermore, the rayleigh scattering length and index of refraction of solid argon and solid xenon at their scintillation wavelengths have not been previously measured or calculated. we introduce a new calculation using existing data in liquid and solid argon and xenon to extrapolate the optical properties at the scintillation wavelengths using the sellmeier dispersion relationship. | index of refraction, rayleigh scattering length, and sellmeier coefficients in solid and liquid argon and xenon |
a search is performed for heavy majorana neutrinos (n) decaying into a w boson and a lepton using the cms detector at the large hadron collider. a signature of two jets and either two same sign electrons or a same sign electron-muon pair is searched for using 19.7 fb-1 of data collected during 2012 in proton-proton collisions at a centre-of-mass energy of 8 tev. the data are found to be consistent with the expected standard model (sm) background and, in the context of a type-1 seesaw mechanism, upper limits are set on the cross section times branching fraction for production of heavy majorana neutrinos in the mass range between 40 and 500 gev. the results are additionally interpreted as limits on the mixing between the heavy majorana neutrinos and the sm neutrinos. in the mass range considered, the upper limits range between 0.00015-0.72 for |ven|2 and 6.6 × 10-5-0.47 for | v en vμn ∗ |2/(| v en|2 + | vμn|2), where vℓn is the mixing element describing the mixing of the heavy neutrino with the sm neutrino of flavour ℓ. these limits are the most restrictive direct limits for heavy majorana neutrino masses above 200 gev. [figure not available: see fulltext.] | search for heavy majorana neutrinos in e±e±+ jets and e± μ ±+ jets events in proton-proton collisions at √{s}=8 tev |
we report cross-section measurements of the final-state muon kinematics for νμ charged-current interactions in the nova near detector using an accumulated 8.09 ×1020 protons on target in the numi beam. we present the results as a double-differential cross section in the observed outgoing muon energy and angle, as well as single-differential cross sections in the derived neutrino energy, eν, and square of the four-momentum transfer, q2. we compare the results to inclusive cross-section predictions from various neutrino event generators via χ2 calculations using a covariance matrix that accounts for bin-to-bin correlations of systematic uncertainties. these comparisons show a clear discrepancy between the data and each of the tested predictions at forward muon angle and low q2, indicating a missing suppression of the cross section in current neutrino-nucleus scattering models. | measurement of the double-differential muon-neutrino charged-current inclusive cross section in the nova near detector |
reconstruction of the b0→ d∗-τ+ντ angular distribution is complicated by the strongly biasing effect of losing the neutrino information from both the b and τ decays. in this work, a novel method for making unbiased measurements of the angular coefficients while preserving the model independence of the angular technique is demonstrated. the twelve angular functions that describe the signal decay, in addition to background terms, are modelled in a multidimensional fit, using template probability density functions that encapsulate all resolution and acceptance effects. sensitivities at the lhcb and belle ii experiments are estimated, and sources of systematic uncertainty are discussed, notably in the extrapolation to a measurement of r(d∗). | model-independent method for measuring the angular coefficients of b 0 → d∗-τ + ντdecays |
we present a detailed qcd analysis of nucleon structure functions x f3(x ,q2) , based on laplace transforms and the jacobi polynomials approach. the analysis corresponds to the next-to-leading order and next-to-next-to-leading order approximations of perturbative qcd. the laplace transform technique, as an exact analytical solution, is used for the solution of nonsinglet dokshitzer-gribov-lipatov-altarelli-parisi evolution equations at low- and large-x values. the extracted results are used as input to obtain the x and q2 evolution of x f3(x ,q2) structure functions using the jacobi polynomials approach. in our work, the values of the typical qcd scale λms¯ (nf) and the strong coupling constant αs(mz2) are determined for four quark flavors (nf=4 ) as well. a careful estimation of the uncertainties shall be performed using the hessian method for the valence-quark distributions, originating from the experimental errors. we compare our valence-quark parton distribution functions sets with those of other collaborations, in particular with the ct14, mmht14, and nnpdf sets, which are contemporary with the present analysis. the obtained results from the analysis are in good agreement with those from the literature. | qcd analysis of nucleon structure functions in deep-inelastic neutrino-nucleon scattering: laplace transform and jacobi polynomials approach |
crystal-damage events such as tracks and point defects have been used to record and detect radiation for a long time and recently they have been proposed as a means for dark-matter detection. color centers can be read out optically and we propose a scheme based on selective plane illumination microscopy for micrometer-scale imaging of large volumes corresponding to kilogram mass detectors. this class of detectors would be passive and would operate at room temperature and we call this the passive low-energy optical color-center nuclear-recoil (paleoccene) detection method. we apply these concepts to the detection of reactor neutrinos using coherent elastic neutrino nucleus scattering (ceν ns). crystal-damage formation energies are intrinsically on the order of 25 ev, resulting in similarly low nuclear-recoil thresholds. this would enable the observation of reactor-neutrino ceν ns with detectors as small as 10 g. additionally, a competitive search for spin-dependent dark-matter scattering down to a dark-matter mass of 0.3 gev could be possible. passive crystal detectors might also be attractive for nuclear-nonproliferation safeguards if used to monitor reactor power and to put limits on plutonium production. the passive nature and small footprint of the proposed detectors implies that these might fit well within accepted reactor-safeguards operations. | passive low-energy nuclear-recoil detection with color centers |
charged current inclusive neutrino-nucleus cross sections are evaluated using the superscaling model for quasielastic scattering and its extension to the pion production region. the contribution of two-particle-two-hole vector meson-exchange current excitations is also considered within a fully relativistic model tested against electron scattering data. the results are compared with the inclusive neutrino-nucleus data from the t2k and sciboone experiments. for experiments where < {e}ν > ∼ 0.8 {{gev}}, the three mechanisms considered in this work provide good agreement with the data. however, when the neutrino energy is larger, effects from beyond the δ also appear to be playing a role. the results show that processes induced by vector two-body currents play a minor role in the inclusive cross sections at the kinematics considered. | charged-current inclusive neutrino cross sections in the superscaling model including quasielastic, pion production and meson-exchange contributions |
in this work, the susav2 and dynamical coupled-channels (dcc) models have been combined and tested in the inelastic regime for electron and neutrino reactions on nuclei. the dcc model, an approach to study baryon resonances through electron and neutrino induced meson production reactions, has been implemented for the first time in the susav2-inelastic model to analyze the resonance region. within this framework, we also present a novel description about other inelasticities in the resonance region (softdis). the outcomes of these approaches are firstly benchmarked against (e , e' ) data on c 12 . the description is thus extended to the study of neutrino-nucleus inclusive cross sections on c 12 and ar 40 and compared with data from the t2k, microboone, argoneut, and minerva experiments, thus covering a wide kinematical range. | superscaling in the resonance region for neutrino-nucleus scattering: the susav2 dynamical coupled-channels model |
longitudinal and transverse responses from inclusive electron scattering are computed within an independent-particle relativistic mean-field model to describe the initial and final states, and one- and two-body current operators leading to the one-particle one-hole response. we find that the two-body contributions have no effect on the longitudinal response but they increase the transverse response by up to 30%, depending on the energy and momentum transfer, improving very significantly the agreement with experimental data. our calculation is fully relativistic and considers within the full quantum mechanical description both the initial and final nucleon states involved in the process, incorporating realistic dynamics. we also show that it is essential to go beyond the plane-wave approach, as incorporating the distortion of the nucleons while making the initial and final states orthogonal, allows to reproduce both the shape and magnitude of the responses. the good agreement with the electron scattering experimental data supports the use of this approach to describe neutrino-induced scattering reaction. | effects of two-body currents in the one-particle one-hole electromagnetic responses within a relativistic mean-field model |
the reconstruction of event-level information, such as the direction or energy of a neutrino interacting in icecube deepcore, is a crucial ingredient to many physics analyses. algorithms to extract this high level information from the detector's raw data have been successfully developed and used for high energy events. in this work, we address unique challenges associated with the reconstruction of lower energy events in the range of a few to hundreds of gev and present two separate, state-of-the-art algorithms. one algorithm focuses on the fast directional reconstruction of events based on unscattered light. the second algorithm is a likelihood-based multipurpose reconstruction offering superior resolutions, at the expense of larger computational cost. | low energy event reconstruction in icecube deepcore |
with excellent energy resolution and ultra-low level radiogenic backgrounds, the high-purity germanium detectors in the majorana demonstrator enable searches for several classes of exotic dark matter (dm) models. in this work we report new experimental limits on kev-scale sterile neutrino dm via the transition magnetic moment from conversion to active neutrinos, $\nu_s \rightarrow \nu_a$. we report new limits on fermionic dark matter absorption ($\chi + a \rightarrow \nu + a$) and sub-gev dm-nucleus 3$\rightarrow$2 scattering ($\chi + \chi + a \rightarrow \phi + a$), and new exclusion limits for bosonic dark matter (axionlike particles and dark photons). these searches utilize the 1--100 kev low energy region of a 37.5 kg-y exposure collected by the demonstrator between may 2016 and nov. 2019, using a set of $^{76}$ge-enriched detectors whose surface exposure time was carefully controlled, resulting in extremely low levels of cosmogenic activation. | exotic dark matter search with the majorana demonstrator |
the quasielastic cross section of charged-current neutrino and antineutrino scattering on 12c is calculated using an improved superscaling model with relativistic effective mass. our model encompasses two-particle emission induced by neutrinos, which we distinguish into two contributions. the first contribution arises from meson-exchange currents, and its calculation is performed at a microscopic level. the second contribution is phenomenological and extracted from the high-energy tail of the scaling function, assumed to be produced by 2p2h mechanisms where the one-body current plays a role, such as short-range correlations and interferences with mec, final-state interaction, etc. the model explicitly includes the modification of the relativistic effective mass of the nucleon within the relativistic mean field model of nuclear matter. the meson exchange currents are also consistently calculated within the same model. with this model, we present predictions for the neutrino and antineutrino cross sections of 12c that have been measured in accelerator experiments. | charged-current quasielastic neutrino scattering from 12c in an extended superscaling model with two-nucleon emission |
the detection and cross-section measurement of coherent elastic neutrino-nucleus scattering (ce{\nu}ns) are vital for particle physics, astrophysics, and nuclear physics. therefore, a new ce{\nu}ns detection experiment is proposed in china. undoped csi crystals, each coupled with two photon multiplier tubes (pmts), will be cooled down to 77k and placed at the china spallation neutron source (csns) to detect the ce{\nu}ns signals produced by neutrinos from stopped pion decays happening within the tungsten target of csns. owing to the extremely high light yield of pure csi at 77k, even though it only has a neutrino flux 60\% weaker than the coherent experiment, the detectable signal event rate is still expected to be 0.074/day/kg (0.053/day/kg for coherent). low radioactivity materials and devices will be used to construct the detector, and strong shielding will be applied to reduce the radioactive and neutron background. dual-pmt readout should be able to reject pmt-related background, such as cherenkov light and pmt dark noise. with all the strategies mentioned above, we hope to reach a 5.1{\sigma} signal detection significance within six months of data taking with a 12kg csi. this presentation will discuss the experiment's design, as well as the estimation of the signal, various kinds of background, and expected signal sensitivity. | ce$\\nu$ns experiment proposal at csns |
neutrinos with energy of order 10 mev, such as from pion decay-at-rest sources, are an invaluable tool for studying low-energy neutrino interactions with nuclei—previously enabling the first measurement of coherent elastic neutrino-nucleus scattering. beyond elastic scattering, neutrinos and dark matter in this energy range also excite nuclei to its low-lying nuclear states, providing an additional physics channel. here, we consider neutral-current inelastic neutrino-nucleus and dark matter (dm)-nucleus scattering off 40ar, 133cs, and 127i nuclei that are relevant to a number of low-threshold neutrino experiments at pion decay-at-rest facilities. we carry out large scale nuclear shell model calculations of the inelastic cross sections considering the full set of electroweak multipole operators. our results demonstrate that gamow-teller transitions provide the dominant contribution to the cross section and that the long-wavelength limit provides a reasonable approximation to the total cross section for neutrino sources. we show that future experiments will be sensitive to this channel, and thus these results provide additional neutrino and dm scattering channels to explore at pion decay-at-rest facilities. | inelastic nuclear scattering from neutrinos and dark matter |
the bayesian approach for feedforward neural networks has been applied to the extraction of the nucleon axial form factor from the neutrino-deuteron-scattering data measured by the argonne national laboratory bubble-chamber experiment. this framework allows to perform a model-independent determination of the axial form factor from data. when the low 0.05 <q2<0.10 -gev2 data are included in the analysis, the resulting axial radius disagrees with available determinations. furthermore, a large sensitivity to the corrections from the deuteron structure is obtained. in turn, when the low-q2 region is not taken into account with or without deuteron corrections, no significant deviations from previous determinations have been observed. a more accurate determination of the nucleon axial form factor requires new precise measurements of neutrino-induced quasielastic scattering on hydrogen and deuterium. | nucleon axial form factor from a bayesian neural-network analysis of neutrino-scattering data |
after the lhc run 1, the standard model (sm) of particle physics has been completed. yet, despite its successes, the sm has shortcomings vis-à-vis cosmological and other observations. at the same time, while the lhc restarts for run 2 at 13 tev, there is presently a lack of direct evidence for new physics phenomena at the accelerator energy frontier. from this state of affairs arises the need for a consistent theoretical framework in which deviations from the sm predictions can be calculated and compared to precision measurements. such a framework should be able to comprehensively make use of all measurements in all sectors of particle physics, including lhc higgs measurements, past electroweak precision data, electric dipole moment, $g-2$, penguins and flavor physics, neutrino scattering, deep inelastic scattering, low-energy $e^{+}e^{-}$ scattering, mass measurements, and any search for physics beyond the sm. by simultaneously describing all existing measurements, this framework then becomes an intermediate step, pointing us toward the next sm, and hopefully revealing the underlying symmetries. we review the role that the standard model effective field theory (smeft) could play in this context, as a consistent, complete, and calculable generalization of the sm in the absence of light new physics. we discuss the relationship of the smeft with the existing kappa-framework for higgs boson couplings characterization and the use of pseudo-observables, that insulate experimental results from refinements due to ever-improving calculations. the lhc context, as well as that of previous and future accelerators and experiments, is also addressed. | through precision straits to next standard model heights |
we present the noise performance of high electron mobility transistors (hemt) developed by cnrs-c2n laboratory. various hemt's gate geometries with 2 pf to 230 pf input capacitance have been studied at 4 k. a model for both voltage and current noises has been developed with frequency dependence up to 1 mhz. these hemts exhibit low dissipation, excellent noise performance and can advantageously replace traditional si-jfets for the readout of high impedance thermal sensor and semiconductor ionization cryogenic detectors. our model predicts that cryogenic germanium detectors of 30 g with 10 ev heat and 20 evee baseline resolution are feasible if read out by hemt based amplifiers. such resolution allows for high discrimination between nuclear and electron recoils at low threshold. this capability is of major interest for coherent elastic neutrino scattering and low-mass dark matter experiments such as ricochet and edelweiss. | low-noise hemts for coherent elastic neutrino scattering and low-mass dark matter cryogenic semiconductor detectors |
a search for new high-mass resonances in proton-proton collisions having final states with an electron or muon and missing transverse momentum is presented. the analysis uses proton-proton collision data collected in 2016 with the cms detector at the lhc at a center-of-mass energy of 13 tev, corresponding to an integrated luminosity of 35.9 fb-1. the transverse mass distribution of the charged lepton-neutrino system is used as the discriminating variable. no significant deviation from the standard model prediction is found. the best limit, from the combination of electron and muon channels, is 5.2 tev at 95% confidence level for the mass of a w' boson with the same couplings as those of the standard model w boson. exclusion limits of 2.9 tev are set on the inverse radius of the extra dimension in the framework of split universal extra dimensions. in addition, model-independent limits are set on the production cross section and coupling strength of w' bosons decaying into this final state. an interpretation is also made in the context of an r parity violating supersymmetric model with a slepton as a mediator and flavor violating decay. | search for high-mass resonances in final states with a lepton and missing transverse momentum at √{s}=13 tev |
we present a novel method to accurately determine the flux of neutrinos and antineutrinos, one of the dominant systematic uncertainty affecting current and future long-baseline neutrino experiments, as well as precision neutrino scattering experiment. using exclusive topologies in ν (ν bar)-hydrogen interactions, νμ p →μ- pπ+, νbarμ p →μ+ pπ-, and νbarμ p →μ+ n with small hadronic energy, we achieve an overall accuracy on the relative fluxes better than 1% in the energy range covering most of the available flux. since we cannot rely on simulations nor model corrections at this level of precision, we present techniques to constrain all relevant systematic uncertainties using data themselves. the method can be implemented using the approach we recently proposed to collect high statistics samples of ν (ν bar)-hydrogen interactions in a low-density and high-resolution detector, which could serve as part of the near detector complex in a long-baseline neutrino experiment, as well as a dedicated beam monitoring detector. | a precise determination of (anti)neutrino fluxes with (anti)neutrino-hydrogen interactions |
a search for new massive particles decaying into a pair of higgs bosons in proton-proton collisions at a center-of-mass energy of 13 tev is presented. data were collected with the cms detector at the lhc, corresponding to an integrated luminosity of 35.9 fb-1. the search is performed for resonances with a mass between 0.8 and 3.5 tev using events in which one higgs boson decays into a bottom quark pair and the other decays into two w bosons that subsequently decay into a lepton, a neutrino, and a quark pair. the higgs boson decays are reconstructed with techniques that identify final state quarks as substructure within boosted jets. the data are consistent with standard model expectations. exclusion limits are placed on the product of the cross section and branching fraction for generic spin-0 and spin-2 massive resonances. the results are interpreted in the context of radion and bulk graviton production in models with a warped extra spatial dimension. these are the best results to date from searches for an hh resonance decaying to this final state, and they are comparable to the results from searches in other channels for resonances with masses below 1.5 tev. | search for resonances decaying to a pair of higgs bosons in the bb ¯qq ¯'ℓν final state in proton-proton collisions at √{s } = 13 tev |
there are broadly three channels to probe axionlike particles (alps) produced in the laboratory: through their subsequent decay to standard model (sm) particles, their scattering with sm particles, or their subsequent conversion to photons. decay and scattering are the most commonly explored channels in beam-dump type experiments, while conversion has typically been utilized by light-shining-through-wall (lsw) experiments. a new class of experiments, dubbed passat (particle accelerator helioscopes for slim axionlike-particle detection), has been proposed to make use of the alp-to-photon conversion in a novel way: alps, after being produced in a beam-dump setup, turn into photons in a magnetic field placed near the source. it has been shown that such hybrid beam-dump-helioscope experiments can probe regions of parameter space that have not been investigated by other laboratory-based experiments, hence providing complementary information; in particular, they probe a fundamentally different region than decay or lsw experiments. we propose the implementation of passat in future neutrino experiments, taking a dune-like experiment as an example. we demonstrate that the magnetic field in the planned dune multipurpose detector is already capable of probing the alp-photon coupling down to ga γ γ∼few ×10-5 gev-1 for alp masses ma≲10 ev . the implementation of a cast or babyiaxo-like magnet would improve the sensitivity down to ga γ γ∼10-6 gev-1 . | passat at future neutrino experiments: hybrid beam-dump-helioscope facilities to probe light axionlike particles |
we discuss prospects for probing z -prime and nonstandard neutrino interactions using neutrino-nucleus coherent scattering with ultralow energy (∼10 ev ) threshold si and ge detectors. the analysis is performed in the context of a specific and contemporary reactor-based experimental proposal, developed in cooperation with the nuclear science center at texas a&m university, and referencing available technology based upon economical and scalable detector arrays. for expected exposures, we show that sensitivity to the z -prime mass is on the order of several tev and is complementary to the lhc search with low-mass detectors in the near term. this technology is also shown to provide sensitivity to the neutrino magnetic moment, at a level that surpasses terrestrial limits, and is competitive with more stringent astrophysical bounds. we demonstrate the benefits of combining silicon and germanium detectors for distinguishing between classes of models of new physics and for suppressing correlated systematic uncertainties. | sensitivity to z -prime and nonstandard neutrino interactions from ultralow threshold neutrino-nucleus coherent scattering |
the katrin experiment is designed for a direct and model-independent determination of the effective electron anti-neutrino mass via a high-precision measurement of the tritium β -decay endpoint region with a sensitivity on mν of 0.2 ev/c2 (90% cl). for this purpose, the β -electrons from a high-luminosity windowless gaseous tritium source traversing an electrostatic retarding spectrometer are counted to obtain an integral spectrum around the endpoint energy of 18.6 kev. a dominant systematic effect of the response of the experimental setup is the energy loss of β -electrons from elastic and inelastic scattering off tritium molecules within the source. we determined the energy-loss function in-situ with a pulsed angular-selective and monoenergetic photoelectron source at various tritium-source densities. the data was recorded in integral and differential modes; the latter was achieved by using a novel time-of-flight technique. we developed a semi-empirical parametrization for the energy-loss function for the scattering of 18.6-kev electrons from hydrogen isotopologs. this model was fit to measurement data with a 95% t2 gas mixture at 30 k, as used in the first katrin neutrino-mass analyses, as well as a d2 gas mixture of 96% purity used in katrin commissioning runs. the achieved precision on the energy-loss function has abated the corresponding uncertainty of σ (mν2) <10-2ev2 [1] in the katrin neutrino-mass measurement to a subdominant level. | precision measurement of the electron energy-loss function in tritium and deuterium gas for the katrin experiment |
we point out that light gauge boson mediators could induce new interference effects in neutrino-electron scattering that can be used to enhance the sensitivity of neutrino-flavor-selective high-intensity neutrino experiments, such as deep underground neutrino experiment (dune). we particularly emphasize a destructive interference effect, leading to a deficit between the standard model expectation and the experimental measurement of the differential cross sections, which is prominent only in either the neutrino or the antineutrino mode, depending on the mediator couplings. therefore, the individual neutrino (or antineutrino) mode could allow for sensitivity reaches superior to the combined analysis and, moreover, could distinguish between different types of gauge boson mediators. | new interference effects from light gauge bosons in neutrino-electron scattering |
a detailed study of charged current quasielastic neutrino and antineutrino scattering cross sections on a 12c target with no pions in the final state is presented. the initial nucleus is described by means of a realistic spectral function s (p ,e ) in which nucleon-nucleon correlations are implemented by using natural orbitals through the jastrow method. the roles played by these correlations and by final-state interactions are analyzed and discussed. the model also includes the contribution of weak two-body currents in the two-particle two-hole sector, evaluated within a fully relativistic fermi gas. the theoretical predictions are compared with a large set of experimental data for double-differential, single-differential, and total integrated cross sections measured by the miniboone, miner ν a , and t2k experiments. good agreement with experimental data is found over the whole range of neutrino energies. the results are also in global good agreement with the predictions of the superscaling approach, which is based on the analysis of electron-nucleus scattering data, with only a few differences seen at specific kinematics. | realistic spectral function model for charged-current quasielastic-like neutrino and antineutrino scattering cross sections on 12c |
gauge-invariant perturbation theory is an extension of ordinary perturbation theory which describes strictly gauge-invariant states in theories with a brout-englert-higgs effect. such gauge-invariant states are composite operators which have necessarily only global quantum numbers. as a consequence, flavor is exchanged for custodial quantum numbers in the standard model, recreating the fermion spectrum in the process. here, we study the implications of such a description, possibly also for the generation structure of the standard model. in particular, this implies that scattering processes are essentially bound-state-bound-state interactions, and require a suitable description. we analyze the implications for the pair-production process e+e-→f¯f at a linear collider to leading order. we show how ordinary perturbation theory is recovered as the leading contribution. using a pdf-type language, we also assess the impact of sub-leading contributions. to lowest order, we find that the result is mainly influenced by how large the contribution of the higgs at large x is. this gives an interesting, possibly experimentally testable, scenario for the formal field theory underlying the electroweak sector of the standard model. | pair production processes and flavor in gauge-invariant perturbation theory |
determining the electron neutrino mass by electron capture in 163ho relies on an accurate understanding of the differential electron capture nuclear decay rate as a function of the distribution of the total decay energy between the neutrino and electronic excitations. the resulting spectrum is dominated by resonances due to local atomic multiplet states with core holes. coulomb scattering between electrons couples the discrete atomic states, via auger-meitner decay, to final states with free electrons. the atomic multiplets are above the auto-ionisation energy, such that the delta functions representing these discrete levels turn into a superposition of lorentzian, mahan- and fano-like line-shapes. we present an ab initio method to calculate nuclear decay modifications due to such processes. it includes states with multiple correlated holes in local atomic orbitals interacting with unbound auger-meitner electrons. a strong energy-dependent, asymmetric broadening of the resonances in good agreement with recent experiments is found. we present a detailed analysis of the mechanisms determining the final spectral line-shape and discuss both the fano interference between different resonances, as well as the energy dependence of the auger-meitner coulomb matrix elements. the latter mechanism is shown to be the dominant channel responsible for the asymmetric line-shape of the resonances in the electron capture spectrum of 163ho. | ab initio calculation of the electron capture spectrum of 163ho: auger-meitner decay into continuum states |
we report a measurement of the energy-dependent total charged-current cross section $\sigma\left(e_\nu\right)$ for inclusive muon neutrinos scattering on argon, as well as measurements of flux-averaged differential cross sections as a function of muon energy and hadronic energy transfer ($\nu$). data corresponding to 5.3$\times$10$^{19}$ protons on target of exposure were collected using the microboone liquid argon time projection chamber located in the fermilab booster neutrino beam with a mean neutrino energy of approximately 0.8 gev. the mapping between the true neutrino energy $e_\nu$ and reconstructed neutrino energy $e^{rec}_\nu$ and between the energy transfer $\nu$ and reconstructed hadronic energy $e^{rec}_{had}$ are validated by comparing the data and monte carlo (mc) predictions. in particular, the modeling of the missing hadronic energy and its associated uncertainties are verified by a new method that compares the $e^{rec}_{had}$ distributions between data and an mc prediction after constraining the reconstructed muon kinematic distributions, energy and polar angle, to those of data. the success of this validation gives confidence that the missing energy in the microboone detector is well-modeled and underpins first-time measurements of both the total cross section $\sigma\left(e_\nu\right)$ and the differential cross section $d\sigma/d\nu$ on argon. | first measurement of energy-dependent inclusive muon neutrino charged-current cross sections on argon with the microboone detector |
a joint fit to neutrino-nucleon scattering and pion electroproduction data is performed to evaluate the nucleon axial form factor in the two-component model consisting of a three-quark intrinsic structure surrounded by a meson cloud. further constraints on the model are obtained by re-evaluating the electromagnetic form factor using electron scattering data. the results of the axial form factor show sizable differences with respect to the widely used dipole model. the impact of such changes on the charged-current quasielastic neutrino-nucleus cross-section is evaluated in the susav2 nuclear model, based on the relativistic mean field and including the contribution of two-body currents. how the different parametrizations of the axial form factor affect the cross-section prediction is assessed in full detail and comparisons to recent t2k and minerva data are presented. | new evaluation of the axial nucleon form factor from electron- and neutrino-scattering data and impact on neutrino-nucleus cross sections |
we present a novel analysis technique for liquid xenon time projection chambers that allows for a lower threshold by relying on events with a prompt scintillation signal consisting of single detected photons. the energy threshold of the lux dark matter experiment is primarily determined by the smallest scintillation response detectable, which previously required a twofold coincidence signal in its photomultiplier arrays, enforced in data analysis. the technique presented here exploits the double photoelectron emission effect observed in some photomultiplier models at vacuum ultraviolet wavelengths. we demonstrate this analysis using an electron recoil calibration dataset and place new constraints on the spin-independent scattering cross section of weakly interacting massive particles (wimps) down to 2.5 gev /c2 wimp mass using the 2013 lux dataset. this new technique is promising to enhance light wimp and astrophysical neutrino searches in next-generation liquid xenon experiments. | extending light wimp searches to single scintillation photons in lux |
within the multiple scattering formulation, the incoherent pion production in neutrino-deuteron reactions at energies near the δ (1232 ) resonance is investigated. the calculations include an impulse term and one-loop contributions from nucleon-nucleon (n n ) and pion-nucleon (π n ) final-state interactions. the input amplitudes of π n scattering and electroweak pion-production reaction on the nucleon are generated from a dynamical model, which describes very extensive data of π n scattering and both the electromagnetic and the weak pion-production reactions on the nucleon. the n n scattering amplitudes are generated from the bonn potential. the validity of the calculational procedures is established by giving a reasonably good description of the data of pion photoproduction on the deuteron. the constructed model is then applied to predict the cross sections of ν +d →μ-+π++n +p and ν +d →μ-+π0+p +p reactions. the importance of including the n n final-state interactions to understand the experimental data of these neutrino-deuteron reactions is demonstrated. our results strongly suggest that the spectator approximation used in the previous analyses to extract the pion-production cross sections on the nucleon from the data on the deuteron is not valid for the ν +d →μ-+π++n +p , but is a good approximation for ν +d →μ-+π0+p +p . | incoherent pion production in neutrino-deuteron interactions |
we show that dark matter with a per-nucleon scattering cross section ≳10-28 cm2 could be discovered by liquid scintillator neutrino detectors like borexino, sno + , and juno. due to the large dark matter fluxes admitted, these detectors could find dark matter with masses up to 1 021 gev , surpassing the mass sensitivity of current direct detection experiments (such as xenon1t and pico) by over 2 orders of magnitude. we derive the spin-independent and spin-dependent cross section sensitivity of these detectors using existing selection triggers, and we propose an improved trigger program that enhances this sensitivity by 2 orders of magnitude. we interpret these sensitivities in terms of three dark matter scenarios: (1) effective contact operators for scattering, (2) qcd-charged dark matter, and (3) a recently proposed model of planck-mass baryon-charged dark matter. we calculate the flux attenuation of dark matter at these detectors due to the earth overburden, taking into account the earth's density profile and elemental composition, as well as nuclear spins. | foraging for dark matter in large volume liquid scintillator neutrino detectors with multiscatter events |
we study future coherent elastic neutrino-nucleus scattering (ce$\nu$ns) modifications from a variety of possible models at the coherent captain mills (ccm) experiment at los alamos. we show that large regions of non-standard neutrino interaction (nsi) parameter space will be excluded rapidly, and that stringent new bounds on the gauge coupling in $z'$ models will also be placed. as a result, ccm will be able to rule out lma-d solutions for a large class of models with mev-scale mediators. | sailing the ce$\\nu$ns seas of non-standard neutrino interactions with the coherent captain mills experiment |
coherent elastic neutrino-nucleus scattering (ceν ns) offers a valuable approach in searching for physics beyond the standard model. the ricochet experiment aims to perform a precision measurement of the ceν ns spectrum at the institut laue-langevin nuclear reactor with cryogenic solid-state detectors. the experiment will employ an array of cryogenic thermal detectors, each with a mass of around 30 g and an energy threshold of 50 ev. one section of this array will contain 9 transition edge sensor (tes)-based calorimeters. the design will not only fulfill requirements for ricochet, but also act as a demonstrator for future neutrino experiments that will require thousands of macroscopic detectors. in this article, we present an updated tes chip design, as well as performance predictions based on a numerical modeling. | transition edge sensor chip design of a modular ceν ns detector for the ricochet experiment |
coherent elastic neutrino-nucleon scattering, challenged by the low nucleus recoil energy of a few tens of kev, has been observed by the coherent experiment using targets csi and ar. we study the contribution of a light $z'$ mediator in a gauged $u(1)_{l_\mu-l_\tau}$ symmetry. in contrast to the mechanism from the kinetic mixing between $u(1)_{\rm em}$ and $u(1)_{l_\mu-l_\tau}$, we adopt a dynamical symmetry breaking of the $u(1)_{l_\mu-l_\tau}$ by employing an extra higgs doublet. as a result, the weak charge mediated by $z'$ only depends on the mass of light gauge boson. since two goldstone bosons are required to serve as the longitudinal components of $z$ and $z'$, the model does not contain a physical cp-odd scalar. using the introduced higgs doublet carrying the $u(1)_{\mu-\tau}$ charge, new higgs decay channels $h\to z_1 z_1/z_1 z_2$ with percent-level branching fractions become accessible. the $w$-mass anomaly observed by cdf ii can be resolved by enhancing the oblique parameter $t$. with the flavored gauge symmetry, the yukawa couplings to fermion flavors are strictly limited. by utilizing the characteristic and introducing a scalar leptoquark $s^{\frac{1}{3}}=(3,1,2/3)$ that uniquely couples to the $\tau$ lepton, the excesses of $r(d)$ and $r(d^*)$ can be explained. moreover, $\tau \to \mu (z_1\to ) e^- e^+$ via the resonant light gauge boson decay can reach the sensitivity of belle ii at an integrated luminosity of 50 ab$^{-1}$. | compatibility of ce$\\nu$ns with muon $g-2$, $w$ mass, and $r(d^{(*)})$ in a gauged ${l_\\mu -l_\\tau}$ with a scalar lq |
the quest for new physics beyond the standard model is boosted by the recently observed deviation in the anomalous magnetic moments of muon and electron from their respective theoretical prediction. in the present work, we have proposed a suitable extension of the minimal lμ − lτ model to address these two experimental results as the minimal model is unable to provide any realistic solution. in our model, a new yukawa interaction involving first generation of leptons, a singlet vector like fermion (χ±) and a scalar (either an su(2)l doublet φ4' or a complex singlet φ4') provides the additional one loop contribution to ae only on top of the usual contribution coming from the lμ− lτ gauge boson (zμτ) to both electron and muon. the judicious choice of lμ − lτ charges to these new fields results in a strongly interacting scalar dark matter in o (mev) range after taking into account the bounds from relic density, unitarity and self interaction. the freeze-out dynamics of dark matter is greatly influenced by 3 → 2 scatterings while the kinetic equilibrium with the sm bath is ensured by 2 → 2 scatterings with neutrinos where zμτ plays a pivotal role. the detection of dark matter is possible directly through scatterings with nuclei mediated by the sm z bosons. moreover, our proposed model can also be tested in the upcoming e+e− colliders by searching opposite sign di-electron and missing energy signal i.e. [inline-graphic not available: see fulltext] at the final state. | (g − 2)e, μ and strongly interacting dark matter with collider implications |
the spallation neutron source (sns) at oak ridge national laboratory is a pulsed source of neutrons and, as a byproduct of this operation, an intense source of pulsed neutrinos via stopped-pion decay. the coherent collaboration uses this source to investigate coherent elastic neutrino-nucleus scattering and other physics with a suite of detectors. this work includes a description of our geant4 simulation of neutrino production at the sns and the flux calculation which informs the coherent studies. we estimate the uncertainty of this calculation at about 10% based on validation against available low-energy pion production data. | simulating the neutrino flux from the spallation neutron source for the coherent experiment |
in this work, we complete our ct18qed study with the neutron's photon parton distribution function (pdf), which is essential for the nucleus scattering phenomenology. two methods, ct18lux and ct18qed, based on the luxqed formalism and the dglap evolution, respectively, to determine the neutron's photon pdf have been presented. various low-$q^2$ non-perturbative variations have been carefully examined, which are treated as additional uncertainties on top of those induced by quark and gluon pdfs. the impacts of the momentum sum rule as well as isospin symmetry violation have been explored, and turn out to be negligible. a detailed comparison with other neutron's photon pdf sets has been performed, which shows a great improvement in the precision and a reasonable uncertainty estimation in our results. finally, two phenomenological implications are demonstrated with photon-initiated processes: neutrino-nucleus $w$-boson production, which is important for the near-future tev--pev neutrino observations, and the axion-like particle production at a high-energy muon beam-dump experiment. | the photon content of the neutron |
miniboone [a. a. aguilar-arevalo et al. (miniboone collaboration), phys. rev. d 83, 052007 (2011), 10.1103/physrevd.83.052007] and minerva (b. eberly et al., arxiv:1406.6415v2 [hep-ex]) charge current π+ production data in the δ region are discussed. it is argued that despite the differences in neutrino flux, they measure the same dynamical mechanism of pion production and should be strongly correlated. the correlation is clearly seen in the monte carlo simulations done with the nuwro generator but is missing in the data. both the normalization and the shape of the ratio of measured differential cross sections in pion kinetic energy are different from the monte carlo results; in the case of normalization the discrepancy is by a factor of 1.49 . | investigation of recent weak single-pion production data |
we present the analysis and results of the first dataset collected with the mars neutron detector deployed at the oak ridge national laboratory spallation neutron source (sns) for the purpose of monitoring and characterizing the beam-related neutron (brn) background for the coherent collaboration. mars was positioned next to the coh-csi coherent elastic neutrino-nucleus scattering detector in the sns basement corridor. this is the basement location of closest proximity to the sns target and thus, of highest neutrino flux, but it is also well shielded from the brn flux by infill concrete and gravel. these data show the detector registered roughly one brn per day. using mars' measured detection efficiency, the incoming brn flux is estimated to be 1.20 ± 0.56 neutrons/m^2/mwh for neutron energies above ~3.5 mev and up to a few tens of mev. we compare our results with previous brn measurements in the sns basement corridor reported by other neutron detectors. | monitoring the sns basement neutron background with the mars detector |
background: long-baseline experiments such as t2k, nova, or the planned deep underground neutrino experiment require theoretical descriptions of the complete event in a neutrino-nucleus reaction. since nuclear targets are used this requires a good understanding of neutrino-nucleus interactions. purpose: one of the dominant reaction channels in neutrino-nucleus interactions is pion production. this paper aims for a theoretically consistent treatment of all charged current charged pion production data that are available from the experiments miniboone, the near detector experiment at t2k, and minerva. method: pion production is treated through excitations of nucleon resonances, including background terms, and deep inelastic scattering. the final state interactions of the produced pions are described within the giessen-boltzmann-uehling-uhlenbeck implementation of quantum-kinetic transport theory. results: results are given for miniboone, the near detector experiment at t2k and for minerva. while the theoretical results for miniboone differ from the data both in shape and magnitude, their agreement both with the t2k and the minerva data is good for all pion and lepton observables. predictions for pion spectra are shown for microboone and nova. conclusions: based on the gibuu model of lepton-nucleus interactions a consistent, good theoretical description of cc charged pion production data from the t2k nd and the minerva experiments is possible, without any parameter tunes. | muon-neutrino-induced charged-current pion production on nuclei |
the propagation velocity of scintillation light in liquid argon vg at λ ~ 128 nm wavelength, has been measured for the first time in a dedicated experimental setup at cern. the obtained result 1/vg = 7.46 ± 0.08 ns/m, is then used to derive the value of the refractive index (n) and the rayleigh scattering length (l) for liquid argon in the vuv region. for λ = 128 nm we found n= 1.358 ± 0.003 and l= 99.1 ± 2.3 cm. the measured values are of interest for a variety of experiments searching for rare events like neutrino and dark matter interactions. the derived quantities also represent key information for theoretical models describing the propagation of scintillation light in liquid argon. | a measurement of the group velocity of scintillation light in liquid argon |
the event rates for wimp-nucleus and neutrino-nucleus scattering processes, expected to be detected in ton-scale rare-event detectors, are investigated. we focus on nuclear isotopes that correspond to the target nuclei of current and future experiments looking for wimp- and neutrino-nucleus events. the nuclear structure calculations, performed in the context of the deformed shell model, are based on hartree-fock intrinsic states with angular momentum projection and band mixing for both the elastic and the inelastic channels. our predictions in the high-recoil-energy tail show that detectable distortions of the measured/expected signal may be interpreted through the inclusion of the nonnegligible incoherent channels. | elastic and inelastic scattering of neutrinos and weakly interacting massive particles on nuclei |
flux-integrated semiexclusive differential and integral cross sections for quasielastic neutrino charged-current scattering on argon are analyzed. the cross sections are calculated using the relativistic distorted-wave impulse approximation and compare with recent microboone data. i found that the measured cross sections can be described well within the experimental uncertainties with value of the nucleon axial mass 1 <ma<1.2 gev . the contribution of the exclusive channel (νμ,μ p ) to the flux-integrated inclusive cross sections is about 50%. | analysis of flux-integrated semiexclusive cross sections for charged-current quasielastic neutrino scattering off 40ar at energies available at the microboone experiment |
fully depleted thick silicon skipper-charge-coupled devices (skipper ccds) are an important technology to probe neutrino and light-dark-matter interactions due to their subelectron read-out noise. however, the successful search for rare neutrino or dark-matter events requires the signal and all backgrounds to be fully characterized. in particular, a measurement of the electron-hole pair creation energy below 150 ev and the fano factor are necessary for characterizing the dark matter and neutrino signals. moreover, photons from background radiation may compton scatter in the silicon bulk, producing events that can mimic a dark matter or neutrino signal. we present a measurement of the compton spectrum using a skipper ccd and a 241am source. with these data, we estimate the electron-hole pair-creation energy to be (3.71 ±0.08 ) ev at 130 k in the energy range between 99.3 ev and 150 ev. by measuring the widths of the steps at 99.3 ev and 150 ev in the compton spectrum, we introduce a novel technique to measure the fano factor, setting an upper limit of 0.31 at 90% c.l. these results prove the potential of skipper ccds to characterize the compton spectrum and to measure precisely the fano factor and electron-hole pair creation energy below 150 ev. | constraints on the electron-hole pair creation energy and fano factor below 150 ev from compton scattering in a skipper ccd |
background: neutrinos in the low-energy regime provide a gateway to a wealth of interesting physics. while plenty of literature exists on detailing the calculation and measurement of total reaction strengths, relatively little attention is paid to the measurement and modeling of the final lepton through differential cross sections at low energies, despite the experimental importance. purpose: we calculate differential cross sections for low-energy neutrino-nucleus scattering. we examine the role played by forbidden transitions in these distributions and how this differs across different energies and nuclear target masses. attention is also paid to predictions for typical experimental neutrino spectra. method: the differential cross sections are calculated within a continuum random-phase approximation framework, which allows us to include collective excitations induced by long-range correlations. the coulomb interaction of the final lepton in charged current events is treated in an effective way. results: kinematic distributions are calculated for 16o, 40ar, and 208pb. the 40ar model results are compared for charged current (cc) (νe,e- ) reactions to events generated by the modeling of argon reaction low-energy yields (marley) event generator [s. gardiner, ph.d. thesis, university of california, davis (2018)], with noticeable discrepancies. conclusion: forbidden transitions have a marked effect on the kinematic distributions of the final lepton at low-energy kinematics, such as for decay-at-rest neutrinos or for a fermi-dirac spectrum at low temperature. this could introduce biases in experimental analyses. backward scattering is noticeably more prominent than with marley. | lepton kinematics in low-energy neutrino-argon interactions |
a large experimental program is underway to extend the sensitivity of direct detection experiments, searching for interaction of dark matter with nuclei, down to the neutrino floor. however, such experiments are becoming increasingly difficult and costly due to the large target masses and exquisite background rejection needed for the necessary improvements in sensitivity. we investigate an alternative approach to the detection of dark matter-nucleon interactions: searching for the persistent traces left by dark matter scattering in ancient minerals obtained from much deeper than current underground laboratories. we estimate the sensitivity of paleo-detectors, which extends far beyond current upper limits for a wide range of dark matter masses. the sensitivity of our proposal also far exceeds the upper limits set by snowden-ifft et al. more than three decades ago using ancient mica in an approach similar to paleo-detectors. | searching for dark matter with paleo-detectors |
we apply effective field theory methods to compute bino-nucleon scattering, in the case where tree-level interactions are suppressed and the leading contribution is at loop order via heavy flavor squarks or sleptons. we find that leading log corrections to fixed-order calculations can increase the bino mass reach of direct detection experiments by a factor of 2 in some models. these effects are particularly large for the bino-sbottom coannihilation region, where bino dark matter as heavy as 5-10 tev may be detected by near future experiments. for the case of stop- and selectron-loop mediated scattering, an experiment reaching the neutrino background will probe thermal binos as heavy as 500 and 300 gev, respectively. we present three key examples that illustrate in detail the framework for determining weak scale coefficients, and for mapping onto a low-energy theory at hadronic scales, through a sequence of effective theories and renormalization group evolution. for the case of a squark degenerate with the bino, we extend the framework to include a squark degree of freedom at low energies using heavy particle effective theory, thus accounting for large logarithms through a "heavy-light current." benchmark predictions for scattering cross sections are evaluated, including complete leading order matching onto quark and gluon operators, and a systematic treatment of perturbative and hadronic uncertainties. | bino variations: effective field theory methods for dark matter direct detection |
we report the measurement of the flux-averaged antineutrino neutral current elastic scattering cross section (d σν ¯n →ν ¯n/d q2) on ch2 by the miniboone experiment using the largest sample of antineutrino neutral current elastic candidate events ever collected. the ratio of the antineutrino to neutrino neutral current elastic scattering cross sections and a ratio of the antineutrino neutral current elastic to antineutrino charged current quasielastic cross sections are also presented. | measurement of the antineutrino neutral-current elastic differential cross section |
we report a measurement of the strange axial coupling constant gas using atmospheric neutrino data at kamland. this constant is a component of the axial form factor of the neutral-current quasielastic (ncqe) interaction. the value of gas significantly changes the ratio of proton and neutron ncqe cross sections. kamland is suitable for measuring ncqe interactions as it can detect nucleon recoils with low-energy thresholds and measure neutron multiplicity with high efficiency. kamland data, including the information on neutron multiplicity associated with the ncqe interactions, makes it possible to measure gas with a suppressed dependence on the axial mass ma, which has not yet been determined. for a comprehensive prediction of the neutron emission associated with neutrino interactions, we establish a simulation of particle emission via nuclear deexcitation of 12c, a process not considered in existing neutrino monte carlo event generators. energy spectrum fitting for each neutron multiplicity gives gas=-0.1 4-0.26+0.25, which is the most stringent limit obtained using ncqe interactions without ma constraints. the two-body current contribution considered in this analysis relies on a theoretically effective model and electron scattering experiments and requires future verification by direct measurements and future model improvement. | first measurement of the strange axial coupling constant using neutral-current quasielastic interactions of atmospheric neutrinos at kamland |
a comparison study of world data for the structure function f2 for iron, as measured by both charged lepton and neutrino scattering experiments, is presented. consistency of results for both charged lepton and neutrino scattering is observed for the full global data set in the valence regime. consistency is also observed at low x for the various neutrino data sets, as well as for the charged lepton data sets, independently. however, data from the two probes exhibit differences on the order of 15% in the shadowing-antishadowing transition region where the bjorken scaling variable x is <0.15 . this observation is indicative that neutrino probes of nucleon structure might be sensitive to different nuclear effects than charged lepton probes. details and results of the data comparison are presented here. | comparison of the structure function f2 as measured by charged lepton and neutrino scattering from iron targets |
nai(tl) crystals are used as particle detectors in a variety of rare-event search experiments because of their superb light-emission quality. the crystal light yield is generally high, above 10 photoelectrons per kev, and its emission spectrum is peaked around 400 nm, which matches well to the sensitive region of bialkali photocathode photomultiplier tubes. however, since nai(tl) crystals are hygroscopic, a sophisticated method of encapsulation has to be applied that prevents moisture from chemically attacking the crystal and thereby degrading the emission. in addition, operation with low energy thresholds, which is essential for a number of new phenomenon searches, is usually limited by the crystal light yield; in these cases higher light yields can translate into lower thresholds that improve the experimental sensitivity. here we describe the development of an encapsulation technique that simplifies the overall design by attaching the photo sensors directly to the crystal so that light losses are minimized. the light yield of a nai(tl) crystal encapsulated with this technique was improved by more than 30%, and as many as 22 photoelectrons per kev have been measured. consequently, the energy threshold can be lowered and the energy resolution improved. detectors with this higher light yield are sensitive to events with sub-kev energies and well suited for low-mass dark matter particle searches and measurements of neutrino-nucleus coherent scattering. | improving the light collection using a new nai(tl) crystal encapsulation |
the miniboone excess persists as a significant puzzle in particle physics. given that the miniboone detector cannot discriminate between electron-like signals and backgrounds due to photons, the goal of this work is to study photon backgrounds in miniboone in depth. we first consider a novel single-photon background arising from multi-nucleon scattering with coherently enhanced initial or final state radiation. this class of processes, which we dub "2p2hγ" (two-particle-two-hole + photon) can explain ~40 of the ~560 excess events observed by miniboone in neutrino mode. second, we consider the background from neutral-current single-π0 production, where two photons from π0 → γγ decay are mis-identified as an electron-like shower. we construct a phenomenological likelihood that reproduces miniboone's π0 → γγ background faithfully. even with data-driven background estimation techniques, we find there is a residual dependence on the monte carlo generator used. our results motivate a reduction in the significance of the miniboone excess by 0.4σ. | more ingredients for an altarelli cocktail at miniboone |
new light, weakly coupled particles can be efficiently produced at existing and future high-intensity accelerators and radioactive sources in deep underground laboratories. once produced, these particles can scatter or decay in large neutrino detectors (e.g. super-k and borexino) housed in the same facilities. we discuss the production of weakly coupled scalars ϕ via nuclear de-excitation of an excited element into the ground state in two viable concrete reactions: the decay of the 0+ excited state of 16o populated via a (p , α) reaction on fluorine and from radioactive 144ce decay where the scalar is produced in the de-excitation of 144nd*, which occurs along the decay chain. subsequent scattering on electrons, e (ϕ , γ) e, yields a mono-energetic signal that is observable in neutrino detectors. we show that this proposed experimental setup can cover new territory for masses 250 kev ≤mϕ ≤ 2me and couplings to protons and electrons, 10-11 ≤gegp ≤10-7. this parameter space is motivated by explanations of the "proton charge radius puzzle", thus this strategy adds a viable new physics component to the neutrino and nuclear astrophysics programs at underground facilities. | probing new physics with underground accelerators and radioactive sources |
the axial form factor plays a crucial role in quasielastic neutrino-nucleus scattering, but the error of the theoretical cross section due to uncertainties of ga remains to be established. conversely, the extraction of ga from the neutrino nucleus cross section suffers from large systematic errors due to nuclear model dependencies, while the use of single-parameter dipole fits underestimates the errors and prevents an identification of the relevant kinematics for this determination. we propose to use a generalized axial-vector-meson dominance in conjunction with large-nc and high-energy qcd constraints to model the nucleon axial form factor, as well as the half-width rule as an a priori uncertainty estimate. the minimal hadronic ansatz comprises the sum of two monopoles corresponding to the lightest axial-vector mesons being coupled to the axial current. the parameters of the resulting axial form factor are the masses and widths of the two axial mesons as obtained from the averaged particle data group values. by applying the half-width rule in a monte carlo simulation, a distribution of theoretical predictions can then be generated for the neutrino-nucleus quasielastic cross section. we test the model by applying it to the (νμ,μ ) quasielastic cross section from 12 for the kinematics of the miniboone experiment. the resulting predictions have no free parameters. we find that the relativistic fermi gas model globally reproduces the experimental data, giving χ2/# bins=0.81 . a q2-dependent error analysis of the neutrino data shows that the uncertainties in the axial form factor ga(q2) are comparable to the ones induced by the a priori half-width rule. we identify the most sensitive region to be in the range 0.2 ≲q2≲0.6 gev2 . | axial-vector dominance predictions in quasielastic neutrino-nucleus scattering |
the deployment of a low-noise 3 kg p-type point contact germanium detector at the dresden-ii power reactor, 8 meters from its 2.96 gw$_{th}$ core, is described. this location provides an unprecedented (anti)neutrino flux of 8.1$\times 10^{13} ~\bar{\nu_{e}}/$cm$^{2}$s. when combined with the 0.2 kev$_{ee}$ detector threshold achieved, a first measurement of ce$\nu$ns from a reactor source appears to be within reach. we report on the characterization and abatement of backgrounds during initial runs, deriving improved limits on extensions of the standard model involving a light vector mediator, from preliminary data. | first results from a search for coherent elastic neutrino-nucleus scattering (ce$\\nu$ns) at a reactor site |
the determination of the electron neutrino mass by electron capture in 163ho relies on a precise understanding of the deexcitation of a core hole after an electron-capture event. here we present an ab initio calculation of the electron-capture spectrum of 163ho, i.e., the 163ho decay rate as a function of the energy distribution between the 163dy daughter atom and the neutrino. our current level of theory includes all intra-atomic decay channels and many-body interactions on a basis of fully relativistic bound orbitals. we use theoretical methods developed and extensively used for the calculation of core level spectroscopy on correlated electron materials. our comparison to experimental electron-capture data critically tests the accuracy of these theories. we find that relativistic interactions beyond the dirac equation lead to only minor shifts of the spectral peaks. the electronic relaxation after an electron-capture event due to the modified nuclear potential leads to a mixing of different edges, but, due to conservation of angular momentum of each scattered electron, no additional structures emerge. many-body coulomb interactions lead to the formation of multiplets and to additional peaks corresponding to multiple core holes created via auger decay. multiplets crucially change the appearance of the resonances on a rydberg energy scale. the additional structures due to auger decay are, although clearly visible, relatively weak compared to the single core hole states and are incidentally far away from the end-point region of the spectrum. as the end point of the spectrum is affected most by the neutrino mass, these additional states do not directly influence the statistics for determining the neutrino mass. the multiplet broadening and auger shake-up of the main core-level edges do, however, change the apparent linewidth and accompanying lifetime of these edges. fitting core-level edges, either in electron-capture spectroscopy or in x-ray absorption spectroscopy, by a single resonance thus leads to an underestimation of the core hole lifetime. | ab initio calculation of the calorimetric electron-capture spectrum of 163ho: intra-atomic decay into bound states |
background: large argon-based neutrino detectors, such as those planned for the deep underground neutrino experiment, have the potential to provide unique sensitivity to low-energy (few to tens of mev) electron neutrinos produced by core-collapse supernovae. despite their importance for neutrino energy reconstruction, nuclear de-excitations following charged-current νe absorption on 40ar have never been studied in detail at supernova energies. purpose: i develop a model of nuclear de-excitations that occur following the 40ar(νe,e−)*40k reaction. this model is applied to the calculation of exclusive cross sections. methods: a simple expression for the inclusive differential cross section is derived under the allowed approximation. nuclear de-excitations are described using a combination of measured γ -ray decay schemes and the hauser-feshbach statistical model. all calculations are carried out using a novel monte carlo event generator called marley (model of argon reaction low energy yields). results: various total and differential cross sections are presented. two de-excitation modes, one involving only γ rays and the other including single neutron emission, are found to be dominant at few tens-of-mev energies. conclusions: nuclear de-excitations have a strong impact on the achievable energy resolution for supernova νe detection in liquid argon. tagging events involving neutron emission, though difficult, could substantially improve energy reconstruction. given a suitable calculation of the inclusive cross section, the marley nuclear de-excitation model may readily be applied to other scattering processes. | nuclear de-excitations in low-energy charged-current νe scattering on 40ar |
the dynamic linear response of a quantum system is critical for understanding both the structure and dynamics of strongly-interacting quantum systems, including neutron scattering from materials, photon and electron scattering from atomic systems, and electron and neutrino scattering by nuclei. we present a general algorithm for quantum computers to calculate the dynamic linear response function with controlled errors and to obtain information about specific final states that can be directly compared to experimental observations. | linear response on a quantum computer |
the connie experiment uses fully depleted, high resistivity ccds as particle detectors in an attempt to measure for the first time the coherent neutrino-nucleus elastic scattering of antineutrinos from a nuclear reactor with silicon nuclei.this talk, given at the xv mexican workshop on particles and fields (mwpf), discussed the potential of connie to perform this measurement, the installation progress at the angra dos reis nuclear power plant, as well as the plans for future upgrades. | the connie experiment |
charged-current neutrino-nucleus scattering is studied in the quasielastic region with the kids (korea-ibs-daegu-skku) nuclear energy density functional. we focus on the uncertainties stemming from the axial mass and the in-medium effective mass of the nucleon. comparing the result of theory to the state-of-the-art data from miniboone, t2k, and minerνa, we constrain the axial mass and the effective mass that are compatible with the data. we find that the total cross section is insensitive to the effective mass, so the axial mass could be determined independently of the uncertainty in the effective mass. differential cross sections at different kinematics are, on the other hand, sensitive to the effective mass as well as the axial mass. within the uncertainty of the axial mass constrained from the total cross section, dependence on the effective mass is examined. as a result we obtain the axial mass and the effective mass that are consistent with the experimental data. | quasielastic charged-current neutrino-nucleus scattering with nonrelativistic nuclear energy density functionals |
in several extensions of the standard model of particle physics (smpp), the neutrinos acquire electromagnetic properties such as the electric millicharge. theoretical and experimental bounds have been reported in the literature for this parameter. in this work, we first carried out a statistical analysis by using data from reactor neutrino experiments, which include elastic neutrino-electron scattering (enes) processes, in order to obtain both individual and combined limits on the neutrino electric millicharge (nem). then we performed a similar calculation to show a estimate of the sensitivity of future experiments of reactor neutrinos to the nem, by involving coherent elastic neutrino-nucleus scattering (cenns). in the first case, the constraints achieved from the combination of several experiments are $-1.1\times 10^{-12}e < q_{\nu} < 9.3\times 10^{-13}e$ ($90\%$ c.l.), and in the second scenario we obtained the bounds $-1.8\times 10^{-14}e < q_{\nu} < 1.8\times 10^{-14}e$ ($90\%$ c.l.). as we will show here, these combined analyses of different experimental data can lead to stronger constraints than those based on individual analysis. where cenns interactions would stand out as an important alternative to improve the current limits on nem. | constraints on neutrino electric millicharge from experiments of elastic neutrino-electron interaction and future experimental proposals involving coherent elastic neutrino-nucleus scattering |
the search for coherent elastic neutrino nucleus scattering (ce$\nu$ns) using reactor antineutrinos represents a formidable experimental challenge, recently boosted by the observation of such a process at the dresden-ii reactor site using a germanium detector. this observation relies on an unexpected enhancement at low energies of the measured quenching factor with respect to the theoretical lindhard model prediction, which implies an extra observable ionization signal produced after the nuclear recoil. a possible explanation for this additional contribution could be provided by the so-called migdal effect, which however has never been observed. here, we study in detail the impact of the migdal contribution to the standard ce$\nu$ns signal calculated with the lindhard quenching factor, finding that the former is completely negligible for observed energies below $\sim 0.3\,\mathrm{kev}$ where the signal is detectable, and thus unable to provide any contribution to ce$\nu$ns searches in this energy regime. to this purpose, we compare different formalisms used to describe the migdal effect that intriguingly show a perfect agreement, making our findings robust. | on the impact of the migdal effect in reactor ce$\\nu$ns experiments |
the paleoccene concept offers the potential for room-temperature, passive and robust detectors in the gram to kilogram range for the detection of low-energy nuclear recoil events. nuclear recoil events can be caused by neutron scattering, coherent elastic neutrino nucleus scattering (cevns) or dark matter scattering and therefore, paleoccene could find applications in all three areas. in this white paper we present current and planned r&d efforts to study the feasibility of this technique. | passive low energy nuclear recoil detection with color centers -- paleoccene |
we consider a scenario where an su(2) triplet scalar acts as the portal for a scalar dark matter particle. we identify regions of the parameter space, where such a triplet coexists with the usual higgs doublet consistently with all theoretical as well as neutrino, accelerator and dark matter constraints, and the triplet-dominated neutral state has substantial invisible branching fraction. lhc signals are investigated for such regions, in the final state same-sign dilepton + ≥ 2 jets +[inline-graphic not available: see fulltext]. while straightforward detectability at the high-luminosity run is predicted for some benchmark points in a cut-based analysis, there are other benchmarks where one has to resort to gradient boosting/neural network techniques in order to achieve appreciable signal significance. | lhc signals of triplet scalars as dark matter portal: cut-based approach and improvement with gradient boosting and neural networks |
distinguishing a dark matter interaction from an astrophysical neutrino-induced interaction will be major challenge for future direct dark matter searches. in this paper, we consider this issue within nonrelativistic effective field theory (eft), which provides a well-motivated theoretical framework for determining nuclear responses to dark matter scattering events. we analyze the nuclear energy recoil spectra from the different dark matter-nucleon eft operators, and compare them to the nuclear recoil energy spectra that are predicted to be induced by astrophysical neutrino sources. we determine that for 11 of the 14 possible operators, the dark matter-induced recoil spectra can be cleanly distinguished from the corresponding neutrino-induced recoil spectra with moderate-size detector technologies that are now being pursued, e.g., these operators would require 0.5 tonne years to be distinguished from the neutrino background for low mass dark matter. our results imply that in most models detectors with good energy resolution will be able to distinguish a dark matter signal from a neutrino signal, without the need for much larger detectors that must rely on additional information from timing or direction. in addition we calculate up-to-date exclusion limits in the eft model space using data from the lux experiment. | effective field theory treatment of the neutrino background in direct dark matter detection experiments |
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