abstract stringlengths 3 192k | title stringlengths 4 857 |
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we study the finite time entanglement dynamics between two dark-soliton qubits due to quantum fluctuations in quasi-one-dimensional bose-einstein condensates. recently, dark solitons are proved to be an appealing platform for qubits due to their appreciably long lifetime. we explore the entanglement decay for an entangled state of two phonon coherences and the qubits to be in the diagonal basis of so-called dicke states. we observe the collapse and revival of the entanglement, depending critically on the collective damping term but independent of the qubit-qubit interaction for both initial states. the collective behavior of the dark-soliton qubits demonstrate the dependence of entanglement evolution on the interatomic distance. | entanglement sudden death and revival in quantum dark-soliton qubits |
we present a minimal grand unified theory model, based on s u (5 ) gauge symmetry and a global u (1 ) peccei-quinn symmetry, that predicts the existence of an ultralight axion dark matter within a narrow mass range of ma∈[0.1 ,4.7 ] nev . this mass window is determined through an interplay between gauge coupling unification constraints, partial proton decay lifetime limits, and the need to reproduce experimentally observed fermion mass spectrum. the entire parameter space of the proposed model will be probed through a synergy between several low-energy experiments that look for proton decay (hyper-kamiokande), axion dark matter through axion-photon coupling (abracadabra and dmradio-gut), and nucleon electric dipole moments (casper electric). | fully testable axion dark matter within a minimal s u (5 ) gut |
a search for dark matter produced in association with a higgs boson decaying to a pair of bottom quarks is performed in proton-proton collisions at a center-of-mass energy of 13 tev collected with the cms detector at the lhc. the analyzed data sample corresponds to an integrated luminosity of 35.9 fb$^{-1}$. the signal is characterized by a large missing transverse momentum recoiling against a bottom quark-antiquark system that has a large lorentz boost. the number of events observed in the data is consistent with the standard model background prediction. results are interpreted in terms of limits both on parameters of the type-2 two-higgs doublet model extended by an additional light pseudoscalar boson a (2hdm+a) and on parameters of a baryonic z' simplified model. the 2hdm+a model is tested experimentally for the first time. for the baryonic z' model, the presented results constitute the most stringent constraints to date. | search for dark matter produced in association with a higgs boson decaying to a pair of bottom quarks in proton-proton collisions at $\\sqrt{s} =$ 13 tev |
the supersymmetrized dfsz axion model is especially compelling in that it contains 1. the susy solution to the gauge hierarchy problem, 2. the peccei-quinn (pq) solution to the strong cp problem and 3. the kim-nilles solution to the susy μ problem. in a string setting, where a discrete r-symmetry (z24r for example) may emerge from the compactification process, a high-quality accidental axion (accion) can emerge from the accidental, approximate remnant global u(1)pq symmetry where the decay constant fa is linked to the susy breaking scale, and is within the cosmological sweet zone. in this setup, one also expects the presence of stringy remnant moduli fields ϕi. here, we consider the situation of a single light modulus ϕ coupled to the pqmssm in the early universe, with mixed axion plus higgsino-like wimp dark matter. we evaluate dark matter and dark radiation production via nine coupled boltzmann equations and assess the severity of the cosmological moduli problem (cmp) along with dark matter and dark radiation production rates. we find that typically the light modulus mass should be mϕ ≳ 104 tev to avoid the moduli-induced dark matter overproduction problem. if one is able to (anthropically) tune the modulus field amplitude, we find a value of ϕ0 ≲ 10-7mp would be required to solve the overall cmp. | dark matter and dark radiation from the early universe with a modulus coupled to the pqmssm |
a large number of studies, all using bayesian parameter inference from markov chain monte carlo methods, have constrained the presence of a decaying dark matter component. all such studies find a strong preference for either very long-lived or very short-lived dark matter. however, in this paper, we demonstrate that this preference is due to parameter volume effects that drive the model towards the standard λ cdm model, which is known to provide a good fit to most observational data. using profile likelihoods, which are free from volume effects, we instead find that the best-fitting parameters are associated with an intermediate regime where around 3% of cold dark matter decays just prior to recombination. with two additional parameters, the model yields an overall preference over the λ cdm model of δ χ2≈-2.8 with planck and bao and δ χ2≈-7.8 with the sh0es h0 measurement, while only slightly alleviating the h0 tension. ultimately, our results reveal that decaying dark matter is more viable than previously assumed, and illustrate the dangers of relying exclusively on bayesian parameter inference when analyzsing extensions to the λ cdm model. | decaying dark matter with profile likelihoods |
a search for heavy resonances, decaying into the standard model vector bosons and the standard model higgs boson, is presented. the final states considered contain a b quark-antiquark pair from the decay of the higgs boson, along with electrons and muons and missing transverse momentum, due to undetected neutrinos, from the decay of the vector bosons. the mass spectra are used to search for a localized excess consistent with a resonant particle. the data sample corresponds to an integrated luminosity of 35.9 fb$^{-1}$ collected in 2016 by the cms experiment at the cern lhc from proton-proton collisions at a center-of-mass energy of 13 tev. the data are found to be consistent with background expectations. exclusion limits are set in the context of spin-0 two higgs doublet models, some of which include the presence of dark matter. in the spin-1 heavy vector triplet framework, mass-degenerate w' and z' resonances with dominant couplings to the standard model gauge bosons are excluded below a mass of 2.9 tev at 95% confidence level. | search for heavy resonances decaying into a vector boson and a higgs boson in final states with charged leptons, neutrinos and b quarks at $\\sqrt{s} =$ 13 tev |
it is shown that in extensions of the standard model of quarks and leptons where the additive lepton number l is broken by two units, so that z2 lepton parity, i.e., (-1 )l which is either even or odd, remains exactly conserved, there is the possibility of stable dark matter without additional symmetry. this applies to many existing simple models of majorana neutrino mass with dark matter, including some radiative models. several well-known examples are discussed. this new insight leads to the construction of a radiative type ii seesaw model of neutrino mass with dark matter where the dominant decay of the doubly charged higgs boson ξ++ is into w+w+ instead of the expected li+lj+ lepton pairs for the well-known tree-level model. | derivation of dark matter parity from lepton parity |
dark matter stability can result from a residual matter-parity symmetry, following naturally from the spontaneous breaking of the gauge symmetry. here we explore this idea in the context of the su(3)c ⊗ su(3)l ⊗ u(1)x ⊗ u(1)n electroweak extension of the standard model. the key feature of our new scotogenic dark matter theory is the use of a triplet scalar boson with anti-symmetric yukawa couplings. this naturally implies that one of the light neutrinos is massless and, as a result, there is a lower bound for the 0 νββ decay rate. | a theory for scotogenic dark matter stabilised by residual gauge symmetry |
the discovery of diffuse sub-pev gamma-rays by the tibet as$_\gamma$ collaboration promises to revolutionize our understanding of the high-energy astrophysical universe. it has been shown that these data broadly agree with prior theoretical expectations. we study the impact of this discovery on a well-motivated new physics scenario: pev-scale decaying dark matter (dm). considering a wide range of final states in dm decay, a number of dm density profiles, and numerous astrophysical background models, we find that these data provide the most stringent limit on dm lifetime for various standard model final states. in particular, we find that the strongest constraints are derived for dm masses in between a few pev to a few tens of pev. near-future data of these high-energy gamma-rays can be used to discover pev-scale decaying dm. | search for dark matter using sub-pev $\\boldsymbol{\\gamma}$-rays observed by tibet as$_{\\boldsymbol{\\gamma}}$ |
in this article we show that in the usual type-i seesaw framework, augmented solely by a neutrino portal interaction, the dark matter (dm) relic density can be created through freeze-in, in a manner fully determined by the seesaw interactions and the dm particle mass. this simple freeze-in scenario, where dark matter is not in a seesaw state, proceeds through slow, seesaw-induced decays of higgs w and z bosons. we identify two scenarios, one of which predicts the existence of an observable neutrino line. | seesaw neutrino determination of the dark matter relic density |
sabre (sodium-iodide with active background rejection) is a new nai(tl) experiment designed to test the dama/libra claim for a positive wimp-dark matter annual modulation signal. sabre will consist of highly pure nai(tl) crystals in an active liquid scintillator veto that will be placed deep underground. the scintillator vessel will provide a veto against external backgrounds and those arising from detector components, especially the 3 kev signature from the decay of 40k in the crystal. through the use of crystal purification techniques and the veto, we aim for a 40k background significantly lower than that of the dama/libra experiment. we present our work developing low-background nai(tl) crystals using a highly pure nai powder and the development of the veto. | sabre: a new nai(t1) dark matter direct detection experiment |
the baryon asymmetry of the universe may be explained by rotations of the qcd axion in field space and baryon number violating processes. we consider the minimal extension of the standard model by a non-abelian gauge interaction, su(2)r, whose sphaleron process violates baryon number. assuming that axion dark matter is also created from the axion rotation by the kinetic misalignment mechanism, the mass scale of the su(2)r gauge boson is fixed as a function of the qcd axion decay constant, and vise versa. significant portion of the parameter space has already been excluded by new gauge boson searches, and the high-luminocity lhc will further probe the viable parameter space. | axiogenesis from su(2)r phase transition |
we introduce the concept of dark space phase transition, which may occur in open many-body quantum systems where irreversible decay, interactions, and quantum interference compete. our study is based on a quantum many-body model that is inspired by classical nonequilibrium processes which feature phase transitions into an absorbing state, such as epidemic spreading. the possibility for different dynamical paths to interfere quantum mechanically results in collective dynamical behavior without classical counterpart. we identify two competing dark states, a trivial one corresponding to a classical absorbing state and an emergent one which is quantum coherent. we establish a nonequilibrium phase transition within this dark space that features a phenomenology which cannot be encountered in classical systems. such emergent two-dimensional dark space may find technological applications, e.g., for the collective encoding of a quantum information. | nonequilibrium dark space phase transition |
we investigate the cosmological evolution of a mimetic matter model with arbitrary scalar potential. the cosmological reconstruction—which is the method for constructing a model for an arbitrary evolution of the scale factor—is explicitly performed for different choices of potential. the cases where the mimetic matter model shows the evolution as cold dark matter (cdm), the w cdm model, dark matter and dark energy with a dynamical o m (z ) [where o m (z )≡[(h (z )/h0)2-1 ]/[(1 +z )3-1 ] ], and phantom dark energy with a phantom-nonphantom crossing are presented in detail. the cosmological perturbations for such evolutions are studied in the mimetic matter model. for instance, the evolution behavior of the matter density contrast (which is different than the usual one, i.e., δ ¨+2 h δ ˙-κ2ρ δ /2 =0 ) is investigated. the possibility of a peculiar evolution of δ in the model under consideration is shown. special attention is paid to the behavior of the matter density contrast near the future singularity, where the decay of perturbations may occur much earlier than the singularity. | cosmological perturbations in a mimetic matter model |
a search for new physics in events with a z boson produced in association with large missing transverse momentum at the lhc is presented. the search is based on the 2016 data sample of proton-proton collisions recorded with the cms experiment at $\sqrt{s} = $ 13 tev, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. the results of this search are interpreted in terms of a simplified model of dark matter production via spin-0 or spin-1 mediators, a scenario with a standard-model-like higgs boson produced in association with the z boson and decaying invisibly, a model of unparticle production, and a model with large extra spatial dimensions. no significant deviations from the background expectations are found, and limits are set on relevant model parameters, significantly extending the results previously achieved in this channel. | search for new physics in events with a leptonically decaying z boson and a large transverse momentum imbalance in proton-proton collisions at $\\sqrt{s} $ = 13 tev |
we study the inert higgs doublet model and its inert scalar higgs $h$ as the only source for dark matter. it is found that three mass regions of the inert scalar higgs can give the correct dark matter relic density. the low mass region (between 3 and 50 gev) is ruled out. new direct dark matter detection experiments will probe the intermediate (between 60 and 100 gev) and high (heavier than 550 gev) mass regions. collider experiments are advised to search for $d^\pm \to hw^\pm$ decay in the two jets plus missing energy channel. | constraints to dark matter from inert higgs doublet model |
recently anomalous flux in the cosmic optical background (cob) is reported by the new horizon observations. the cob flux is 16.37 ±1.47 n wm−2 sr−1 , at the lorri pivot wavelength of 0.608 μ m , which is ∼4 σ level above the expected flux from the hubble space telescope (hst) galaxy count. it would be great if this were a hint for the ev scale dark matter decaying into photons. in this paper, we point out that such a decaying dark matter model predicts a substantial amount of anisotropy in the cob flux, which is accurately measured by the hst. the data of the hst excludes the decay rate of the dominant cold dark matter larger than 10-24- 10-23 s-1 in the mass range of 5-20 ev. as a result, the decaying cold dark matter explaining the cob excess is strongly disfavored by the anisotropy bound. we discuss some loopholes: e.g., warm/hot dark matter or two-step decay of the dark matter to explain the cob excess. | anisotropic cosmic optical background bound for decaying dark matter in light of the lorri anomaly |
we studied the spin depolarization of ensembles of nitrogen-vacancy (nv) centers in nitrogen-rich single-crystal diamonds. we found a strong dependence of the evolution of the polarized state in the dark on the concentration of nv centers. at low excitation power, we observed a simple exponential decay profile in the low-density regime and a paradoxical inverted exponential profile in the high-density regime. at higher excitation power, we observed complex behavior, with an initial sharp rise in the luminescence signal after the preparation pulse followed by a slower exponential decay. magnetic field and excitation laser power-dependent measurements suggest that the rapid initial increase of the luminescence signal is related to recharging of the nitrogen-vacancy centers (from neutral to negatively charged) in the dark. the slow relaxing component corresponds to the longitudinal spin relaxation of the nv ensemble. the shape of the decay profile reflects the interplay between two mechanisms: the nv charge-state conversion in the dark and the longitudinal spin relaxation. these mechanisms, in turn, are influenced by ionization, recharging, and polarization dynamics during excitation. interestingly, we found that charge dynamics are dominant in nv-dense samples even at very feeble excitation power. these observations may be important for the use of ensembles of nv centers in precession magnetometry and sensing applications. | coupled charge and spin dynamics in high-density ensembles of nitrogen-vacancy centers in diamond |
we test the origin of the 3.5 kev line photons by analyzing the morphology of the emission at that energy from the galactic center and from the perseus cluster of galaxies. we employ a variety of different templates to model the continuum emission and analyze the resulting radial and azimuthal distribution of the residual emission. we then perform a pixel-by-pixel binned likelihood analysis including line emission templates and dark matter templates and assess the correlation of the 3.5 kev emission with these templates. we conclude that the radial and azimuthal distribution of the residual emission is incompatible with a dark matter origin for both the galactic center and perseus; the galactic center 3.5 kev line photons trace the morphology of lines at comparable energy, while the perseus 3.5 kev photons are highly correlated with the cluster's cool core, and exhibit a morphology incompatible with dark matter decay. the template analysis additionally allows us to set the most stringent constraints to date on lines in the 3.5 kev range from dark matter decay. | where do the 3.5 kev photons come from? a morphological study of the galactic center and of perseus |
we make a comprehensive study of vector-like fermionic dark matter and flavor anomalies in a simple extension of standard model. the model is added with doublet vector-like fermions of quark and lepton types, and also a $s_1(\bar{\textbf{3}},\textbf{1},1/3)$ scalar leptoquark. an additional lepton type singlet fermion is included, whose admixture with vector-like lepton doublet plays the role of dark matter and is examined in relic density and direct detection perspective. electroweak precision observables are computed to put constraint on model parameter space. we constrain the new couplings from the branching ratios and angular observables associated with $b \to sll (\nu_l \bar \nu_l)$, $b \to s \gamma$ decays and also from the recent measurement on muon anomalous magnetic moment. we then estimate the branching ratios of the rare lepton flavor vioalting $b_{(s)}$ decay modes such as $b_{(s)} \to l_i^\mp l_j^\pm$, $b_{(s)} \to (k^{(*)}, \phi) l_i^\mp l_j^\pm$. | dark matter and flavor anomalies in the light of vector-like fermions and scalar leptoquark |
nucleon decays are generic predictions of motivated theories, including those based on the unification of forces and supersymmetry. we demonstrate that non-canonical nucleon decays offer a unique opportunity to broadly probe light new particles beyond the standard model with masses below $\sim$few gev over decades in mass range, including axion-like particles, dark photons, sterile neutrinos, and scalar dark matter. conventional searches can misinterpret and even completely miss such new physics. we propose a general strategy based on momenta of visible decay final states to probe these processes, offering a rich physics program for existing and upcoming experiments such as super-kamiokande, hyper-kamiokande, dune, and juno. | non-canonical nucleon decays as window into light new physics |
we study a lepton-flavored dark matter model and its signatures at a future muon collider. we focus on the less-explored regime of feeble dark matter interactions, which suppresses the dangerous lepton-flavor violating processes, gives rise to dark matter freeze-in production, and leads to long-lived particle signatures at colliders. we find that the interplay of dark matter freeze-in and its mediator freeze-out gives rise to an upper bound of around tev scales on the dark matter mass. the signatures of this model depend on the lifetime of the mediator, and can range from generic prompt decays to more exotic long-lived particle signals. in the prompt region, we calculate the signal yield, study useful kinematics cuts, and report tolerable systematics that would allow for a $5\sigma$ discovery. in the long-lived region, we calculate the number of charged tracks and displaced lepton signals of our model in different parts of the detector, and uncover kinematic features that can be used for background rejection. we show that, unlike in hadron colliders, multiple production channels contribute significantly which leads to sharply distinct kinematics for electroweakly-charged long-lived particle signals. ultimately, the collider signatures of this lepton-flavored dark matter model are common amongst models of electroweak-charged new physics, rendering this model a useful and broadly applicable benchmark model for future muon collider studies that can help inform work on detector design and studies of systematics. | a duet of freeze-in and freeze-out: lepton-flavored dark matter and muon colliders |
a new understanding of the stability of self-interacting dark matter is pointed out, based on the simplest spontaneously broken abelian u (1) gauge model with one complex scalar and one dirac fermion. the key is the imposition of dark charge conjugation symmetry. it allows the possible existence of two stable particles: the dirac fermion and the vector gauge boson which acts as a light mediator for the former's self-interaction. since this light mediator does not decay, it avoids the strong cosmological constraints recently obtained for all such models where the light mediator decays into standard-model particles. | inception of self-interacting dark matter with dark charge conjugation symmetry |
we study the cosmological consequences of codecaying dark matter—a recently proposed mechanism for depleting the density of dark matter through the decay of nearly degenerate particles. a generic prediction of this framework is an early dark matter dominated phase in the history of the universe, that results in the enhanced growth of dark matter perturbations on small scales. we compute the duration of the early matter dominated phase and show that the perturbations are robust against washout from free streaming. the enhanced small-scale structure is expected to survive today in the form of compact microhalos and can lead to significant boost factors for indirect-detection experiments, such as fermi, where dark matter would appear as point sources. | concentrated dark matter: enhanced small-scale structure from codecaying dark matter |
we constrain the higgs-portal model employing the vector-boson fusion channel at the lhc. in particular, we include the phenomenologically interesting parameter region near the higgs resonance, where the higgs-boson mass is close to the threshold for dark-matter production and a running-width prescription has to be employed for the higgs- boson propagator. limits for the higgs-portal coupling as a function of the dark-matter mass are derived from the cms search for invisible higgs-boson decays in vector-boson fusion at 13 tev. furthermore, we perform projections for the 14 tev hl-lhc and the 27 tev he-lhc taking into account a realistic estimate of the systematic uncertainties. the respective upper limits on the invisible branching ratio of the higgs boson reach a level of 2% and constrain perturbative higgs-portal couplings up to dark-matter masses of about 110 gev. | probing higgs-portal dark matter with vector-boson fusion |
proton beam dumps are prolific sources of mesons enabling a powerful technique to search for vector mediator coupling of dark matter to neutral pion and higher mass meson decays. by the end of the decade the pip-ii linac will be delivering up to 1 mw of proton power to the fnal campus. this includes a significant increase of power to the booster neutrino beamline (bnb) which delivers 8 gev protons to the short baseline neutrino (sbn) detectors. by building a new dedicated beam dump target station, and using the sbn detectors, a greater than an order of magnitude increase in search sensitivity for dark matter relative to the recent miniboone beam dump search can be achieved. this modest cost upgrade to the bnb would begin testing models of the highly motivated relic density limit predictions and provide novel ways to test explanations of the anomalous excess of low energy events seen by miniboone. | sbn-bd: $\\mathcal{o}$(10 gev) proton beam dump at fermilab's pip-ii linac |
in minimal supersymmetric su(5) models, the proton can decay through dimension 5 operators. since this decay depends directly on the supersymmetric soft masses, it will be constrained by other observables which depend on the soft masses, such as the higgs mass and the dark matter relic density. in this work, we will examine the upper limit on the proton lifetime in minimal supersymmetric su(5) with constrained minimal supersymmetric (cmssm) boundary conditions set at the grand unification scale. we perform a random scan over the variables of the (cmssm), with of order 106 points, and find that the proton lifetime is within reach of juno and hyper-kamiokande's experiment. | upper limit on the proton lifetime in minimal supersymetric su(5) |
we study the nonequilibrium dynamics of axionlike particles (alp) coupled to standard model degrees of freedom in thermal equilibrium. the quantum master equation (qme) for the alp reduced density matrix is derived to leading order in the coupling of the alp to the thermal bath, but to all orders of the bath couplings to degrees of freedom within or beyond the standard model other than the alp. the qme describes the damped oscillation dynamics of an initial misaligned alp condensate, thermalization with the bath, decoherence, and entropy production within a unifying framework. the alp energy density e (t ) features two components: a "cold" component from the misaligned condensate and a "hot" component from thermalization with the bath, with e (t )=ece-γ (t )t+eh(1 -e-γ (t )t) thus providing a "mixed dark matter" scenario. relaxation of the alp condensate, thermalization, decoherence, and entropy production occur on similar timescales. an explicit example with alp-photon coupling, valid post recombination yields a relaxation rate γ (t ) with a substantial enhancement from thermal emission and absorption. a misaligned condensate is decaying at least since recombination and on the same timescale thermalizing with the cosmic microwave background (cmb). possible consequences for birefringence of the cmb and alp contribution to the effective number of ultrarelativistic species and galaxy formation are discussed. | nonequilibrium dynamics of axionlike particles: the quantum master equation |
we test a novel idea of using a π- beam in the fixed-target experiments to search for new physics in the events with missing energy. bounds for invisible vector ρ meson decay were derived, analyzed, and compared with the current limits on searching dark matter in the accelerator based experiments. we demonstrate that the new approach can be effective tool to probe sub-gev dark matter parameter space. | probing invisible vector meson decay mode with the hadronic beam in the na64 experiment at sps cern |
we present a detailed study of a scotogenic model accommodating dark matter, neutrino masses and the anomalous magnetic moment of the muon while being consistent with the existing constraints on flavour violating decays of the leptons. moreover, this model offers the possibility to explain the baryon asymmetry of the universe via leptogenesis. we determine the viable regions of the model's parameter space in view of dark matter and flavour constraints using a markov chain monte carlo setup combined with a particular procedure to accommodate neutrino masses and the anomalous magnetic moment of the muon at the same time. we also discuss briefly the resulting collider phenomenology. | accommodating muon (g − 2) and leptogenesis in a scotogenic model |
we present here a characterization of the low background nai(tl) crystal nai-33 based on a period of almost one year of data taking (891 kg×days exposure) in a detector configuration with no use of organic scintillator veto. this remarkably radio-pure crystal already showed a low background in the sabre proof-of-principle (pop) detector, in the low energy region of interest (1-6 kev) for the search of dark matter interaction via the annual modulation signature. as the vetoable background components, such as 40k, are here sub-dominant, we reassembled the pop setup with a fully passive shielding. we upgraded the selection of events based on a boosted decision tree algorithm that rejects most of the pmt-induced noise while retaining scintillation signals with > 90% efficiency in 1-6 kev. we find an average background of 1.39 ± 0.02 counts/day/kg/kev in the region of interest and a spectrum consistent with data previously acquired in the pop setup, where the external veto background suppression was in place. our background model indicates that the dominant background component is due to decays of 210pb, only partly residing in the crystal itself. the other location of 210pb is the reflector foil that wraps the crystal. we now proceed to design the experimental setup for the physics phase of the sabre north detector, based on an array of similar crystals, using a low radioactivity ptfe reflector and further improving the passive shielding strategy, in compliance with the new safety and environmental requirements of laboratori nazionali del gran sasso. | performance of the sabre detector module in a purely passive shielding |
a search is performed for events consistent with the pair production of a new heavy particle that acts as a mediator between a dark sector and normal matter, and that decays to a light quark and a new fermion called a dark quark. the search is based on data corresponding to an integrated luminosity of 16.1 fb-1 from proton-proton collisions at √{s}=13 tev collected by the cms experiment at the lhc in 2016. the dark quark is charged only under a new quantum-chromodynamics-like force, and forms an "emerging jet" via a parton shower, containing long-lived dark hadrons that give rise to displaced vertices when decaying to standard model hadrons. the data are consistent with the expectation from standard model processes. limits are set at 95% confidence level excluding dark pion decay lengths between 5 and 225 mm for dark mediators with masses between 400 and 1250 gev. decay lengths smaller than 5 and greater than 225 mm are also excluded in the lower part of this mass range. the dependence of the limit on the dark pion mass is weak for masses between 1 and 10 gev. this analysis is the first dedicated search for the pair production of a new particle that decays to a jet and an emerging jet. | search for new particles decaying to a jet and an emerging jet |
the xenon1t experiment aims for the direct detection of dark matter in a detector filled with 3.3 tons of liquid xenon. in order to achieve the desired sensitivity, the background induced by radioactive decays inside the detector has to be sufficiently low. one major contributor is the β -emitter ^{85}kr which is present in the xenon. for xenon1t a concentration of natural krypton in xenon ^{nat}kr/xe < 200 ppq (parts per quadrillion, 1 ppq =10^{-15} mol/mol) is required. in this work, the design, construction and test of a novel cryogenic distillation column using the common mccabe-thiele approach is described. the system demonstrated a krypton reduction factor of 6.4\cdot 10^5 with thermodynamic stability at process speeds above 3 kg/h. the resulting concentration of ^{nat}kr/xe<26 ppq is the lowest ever achieved, almost one order of magnitude below the requirements for xenon1t and even sufficient for future dark matter experiments using liquid xenon, such as xenonnt and darwin. | removing krypton from xenon by cryogenic distillation to the ppq level |
prerecombination acoustic oscillations induce nonadiabatic perturbations between baryons and dark matter, corresponding to a constant relative-density δb c and decaying relative-velocity perturbation vb c . due to their significant large-scale correlations and prominent baryon acoustic oscillation (bao) features, these modes are potentially important for the use of the bao as standard ruler. we present a complete treatment of the effects of the baryon-cold dark matter perturbations on galaxy clustering in the context of a rigorous perturbative bias expansion. the leading effects are proportional to δb c and θb c=∂ivbc i. we estimate the magnitude of these terms through the excursion set approach. the contribution from vbc 2, which has attracted significant attention recently, contributes at subleading (one-loop) order. the relative-density contribution δb c is expected to be by far the largest contribution. we also point out contributions to the galaxy velocity bias, the largest of which is simply vb c, leading to a term ∝μ2θb c in the redshift-space galaxy power spectrum pgs(k ,μ ). complete expressions of the galaxy power spectrum at one-loop order are given, which contain several new terms. | effect of relative velocity and density perturbations between baryons and dark matter on the clustering of galaxies |
we consider decaying dark matter with masses 1 07≲m ≲1 016 gev as a source of ultrahigh energy (uhe) gamma rays. using recent limits on uhe gamma-ray flux for energies eγ>2 ×1 014 ev , provided by extensive air shower observatories, we put limits on masses and lifetimes of the dark matter. we also discuss possible dark matter decay origin of tentative 100 pev photon flux detected with the eas-msu experiment. | constraining heavy decaying dark matter with the high energy gamma-ray limits |
a search is presented for dark matter produced in association with a hadronically decaying w or z boson using 3.2 /fb of pp collisions at $\sqrt{s}$=13 tev recorded by the atlas detector at the large hadron collider. events with a hadronic jet compatible with a w or z boson and with large missing transverse momentum are analysed. the data are consistent with the standard model predictions and are interpreted in terms of both an effective field theory and a simplified model containing dark matter. | search for dark matter produced in association with a hadronically decaying vector boson in pp collisions at $\\sqrt{s}$=13 tev with the atlas detector |
this paper describes a search for events with one top-quark and large missing transverse momentum in the final state. data collected during 2015 and 2016 by the atlas experiment from 13 tev proton-proton collisions at the lhc corresponding to an integrated luminosity of 36.1 fb-1 are used. two channels are considered, depending on the leptonic or the hadronic decays of the w boson from the top quark. the obtained results are interpreted in the context of simplified models for dark-matter production and for the single production of a vector-like t quark. in the absence of significant deviations from the standard model background expectation, 95% confidence-level upper limits on the corresponding production cross-sections are obtained and these limits are translated into constraints on the parameter space of the models considered. [figure not available: see fulltext.] | search for large missing transverse momentum in association with one top-quark in proton-proton collisions at √{s} = 13 tev with the atlas detector |
while the higgs characterisation programme is well under way, direct signs for new physics beyond the standard model remain elusive. performing a fit of fully differential higgs production cross sections at the lhc to a subset of higgs-relevant effective operators, we discuss the extent to which theoretical uncertainties can limit the sensitivity in such a new physics search programme. extending the dimension-6 higgs effective field theory framework by introducing new light degrees of freedom that can contribute to an invisible (or undetectable) higgs decay width h→ φ φ , we show how differential coupling fits can disentangle effects from non-standard model couplings and an invisible decay width, as present in many new physics scenarios, such as higgs-portal dark matter. including the so-called off-shell measurement that has been advocated as a sensitive determination of the higgs width in the κ framework, we show explicitly that this method does not provide complementary sensitivity for scale-separated new physics λ ≫ m_h ≫ m_φ , which is favoured in beyond the standard model scenarios that relate astrophysics and collider phenomenology in the light of non-observation of new physics during run 1 of the lhc. | higgs characterisation in the presence of theoretical uncertainties and invisible decays |
we perform a combined likelihood analysis for the icecube 6-year high-energy starting events (hese) above 60 tev and 8-year throughgoing muon events above 10 tev using a two-component neutrino flux model. the two-component flux can be motivated either from purely astrophysical sources or due to a beyond standard model contribution, such as decaying heavy dark matter. as for the astrophysical neutrinos, we consider two different source flavor compositions corresponding to the standard pion decay and muon-damped pion decay sources. we find that the latter is slightly preferred over the former as the high-energy component, while the low-energy component does not show any such preference. we also take into account the multi-messenger gamma-ray constraints and find that our two-component fit is compatible with these constraints, whereas the single-component power-law bestfit to the hese data is ruled out. the astrophysical plus dark matter interpretation of the two-component flux is found to be mildly preferred by the current data and the gamma-ray constraints over the purely astrophysical explanation. | a combined astrophysical and dark matter interpretation of the icecube hese and throughgoing muon events |
we explore the dirac fermionic and complex scalar dark matter in the framework of a hidden u (1 )x gauge theory with kinetic mixing between the u (1 )x and u (1 )y gauge fields. the u (1 )x gauge symmetry is spontaneously broken due to a hidden higgs field. the kinetic mixing provides a portal between dark matter and standard model particles. besides, an additional higgs portal can be realized in the complex scalar case. dark matter interactions with nucleons are typically isospin violating, and direct detection constraints can be relieved. although the kinetic mixing has been stringently constrained by electroweak oblique parameters, we find that there are several available parameter regions predicting an observed relic abundance through the thermal production mechanism. moreover, these regions have not been totally explored in current direct and indirect detection experiments. future direct detection experiments and searches for invisible higgs decays at a higgs factory could further investigate these regions. | fermionic and scalar dark matter with hidden u(1) gauge interaction and kinetic mixing |
we investigate constraints on some key cosmological parameters by confronting metastable dark energy (de) models with different combinations of the most recent cosmological observations. along with the standard λcdm model, two phenomenological metastable de models are considered: (i) de decays exponentially, (ii) de decays into dark matter. we find that: (1) when considering the most recent supernovae and bao data, and assuming a fiducial λcdm model, the inconsistency in the estimated value of the {{{ω }}}{{m},0}{h}2 parameter obtained by either including or excluding planck cosmic microwave background (cmb) data becomes very much substantial and points to a clear tension; (2) although the two metastable de models that we study provide greater flexibility in fitting the data, and they indeed fit the supernovae (sne) ia+bao data substantially better than λcdm, they are not able to alleviate this tension significantly when cmb data are included; (3) while local measurements of the hubble constant are significantly higher relative to the estimated value of h 0 in our models (obtained by fitting to sne ia and bao data), the situation seems to be rather complicated with hints of inconsistency among different observational data sets (cmb, sne ia+bao, and local h 0 measurements). our results indicate that we might not be able to remove the current tensions among different cosmological observations by considering simple modifications of the standard model or by introducing minimal de models. a complicated form of expansion history, different systematics in different data and/or a nonconventional model of the early universe might be responsible for these tensions. | revisiting metastable dark energy and tensions in the estimation of cosmological parameters |
recently, the atlas and cms collaborations report excesses around 750 gev in the diphoton channels. this might be the evidence which reveals new physics beyond the standard model. in this paper, we consider models with a 750 gev scalar and vectorlike particles, which couple each other through yukawa couplings. the decay of the scalar to diphoton is given by the loop diagrams involving the extra colored particles. we investigate not only the setup required by the excesses, but also the lhc constraints, especially concerned with the vectorlike particles. in our scenario, the extra colored particles decay to quarks and a dark matter (dm) via yukawa couplings. then, the signals from the vectorlike particles are dijet, b b ¯ and/or t t ¯ with large missing energy. we discuss two possibilities for the setups: one is a model with vectorlike fermions and a scalar dm, and the other is a model with vectorlike scalars and a fermionic dm. we suggest the parameter region favored by the excess in each case, and study the constraints based on the latest lhc results at √{s }=8 tev and 13 tev. we conclude that the favored region is almost excluded by the lhc bounds, especially when the 750 gev scalar dominantly decays to dms. the mass differences between the vectorlike particles and the dm should be less than o (100 ) gev [o (10 ) gev ] to realize the large diphoton signal and the large decay width, if the extra colored particle only decays to a top (bottom) quark and a dark matter. otherwise, these scenarios are already excluded by the latest lhc results. | diphoton excess at 750 gev and lhc constraints in models with vectorlike particles |
we show that the present dark matter abundance can be accounted for by an oscillating scalar field that acquires both mass and a non-zero expectation value from interactions with the higgs field. the dark matter scalar field can be sufficiently heavy during inflation, due to a non-minimal coupling to gravity, so as to avoid the generation of large isocurvature modes in the cmb anisotropies spectrum. the field begins oscillating after reheating, behaving as radiation until the electroweak phase transition and afterwards as non-relativistic matter. the scalar field becomes unstable, although sufficiently long-lived to account for dark matter, due to mass mixing with the higgs boson, decaying mainly into photon pairs for masses below the mev scale. in particular, for a mass of ∼7 kev, which is effectively the only free parameter, the model predicts a dark matter lifetime compatible with the recent galactic and extragalactic observations of a 3.5 kev x-ray line. | scalar field dark matter with spontaneous symmetry breaking and the 3.5 kev line |
as we have pointed out in (arxiv:arxiv:1806.10107 [hep-ph]), the existence of neutron dark matter decay modes n → χ + anything, where χ is a dark matter fermion, for the solution of the neutron lifetime problem changes priorities and demands to describe the neutron lifetime τn = 888.0 (2.0) s, measured in beam experiments and defined by the decay modes n → p + anything, in the standard model (sm). the latter requires the axial coupling constant λ to be equal to λ = - 1.2690 (arxiv:arxiv:1806.10107 [hep-ph]). since such an axial coupling constant is excluded by experimental data reported by the perkeo ii and ucna collaborations, the neutron lifetime τn = 888.0 (2.0) s can be explained only by virtue of interactions beyond the sm, namely, by the fierz interference term of order b ∼ -10-2 dependent on scalar and tensor coupling constants. we give a complete analysis of all correlation coefficients of the neutron β--decays with polarized neutron, taking into account the contributions of scalar and tensor interactions beyond the sm with the fierz interference term b ∼ -10-2. we show that the obtained results agree well with contemporary experimental data that does not prevent the neutron with the rate of the decay modes n → p + anything, measured in beam experiments, to have dark matter decay modes n → χ + anything. | neutron dark matter decays and correlation coefficients of neutron β--decays |
we propose a complete cosmological scenario based on a flipped su (5) × u (1) gut model that incorporates starobinsky-like inflation, taking the subsequent cosmological evolution carefully into account. a single master coupling, λ6, connects the singlet, gut higgs and matter fields, controlling 1) inflaton decays and reheating, 2) the gravitino production rate and therefore the non-thermal abundance of the supersymmetric cold dark matter particle, 3) neutrino masses and 4) the baryon asymmetry of the universe. | cosmology with a master coupling in flipped su(5)×u(1): the λ6 universe |
we propose a two-component dark matter explanation to the edges 21 cm anomalous signal. the heavier dark matter component is long-lived, and its decay is primarily responsible for the relic abundance of the lighter dark matter, which is millicharged. to evade the constraints from cmb, underground dark matter direct detection, and xqc experiments, the lifetime of the heavier dark matter has to be larger than $ 0.1\, \tau_u $ , where $ \tau_u $ is the age of the universe. our model provides a viable realization of the millicharged dark matter model to explain the edges 21 cm signal, since the minimal model in which the relic density is generated via thermal freeze-out has been ruled out by various constraints. *supported in part by the national natural science foundation of china (11775109) | two-component millicharged dark matter and the edges 21 cm signal |
we consider the freeze-in production of 7 kev axino dark matter (dm) in the supersymmetric dine-fischler-srednicki-zhitnitsky (dfsz) model in light of the 3.5 kev line excess. the warmness of such 7 kev dm produced from the thermal bath, in general, appears in tension with ly-α forest data, although a direct comparison is not straightforward. this is because the ly-α forest constraints are usually reported on the mass of the conventional warm dark matter (wdm), where large entropy production is implicitly assumed to occur in the thermal bath after wdm particles are decoupled. the phase space distribution of freeze-in axino dm varies depending on production processes and axino dm may alleviate the tension with the tight ly-α forest constraints. by solving the boltzmann equation, we first obtain the resultant phase space distribution of axinos produced by 2-body decay, 3-body decay, and 2-to-2 scattering respectively. the reduced collision term and resultant phase space distribution are useful for studying other freeze-in scenarios as well. we then calculate the resultant linear matter power spectra for such axino dm and directly compare them with the linear matter power spectra for the conventional wdm . in order to demonstrate realistic axino dm production, we consider benchmark points with higgsino next-to-light supersymmetric particle (nlsp) and wino nlsp. in the case of higgsino nlsp, the phase space distribution of axinos is colder than that in the conventional wdm case, so the most stringent ly-α forest constraint can be evaded with mild entropy production from saxion decay inherent in the supersymmetric dfsz axion model. | light axinos from freeze-in: production processes, phase space distributions, and ly-α forest constraints |
we study the stochastic axion dark matter scenario in the axion landscape, where one of the axions is light and stable and therefore explains dark matter. if the axion mass at the potential is a typical value of the curvature along the direction, the potential can be well approximated by a quadratic mass term. on the other hand, if the axion mass happens to be suppressed in the vicinity of the minimum, the potential may be approximated by a quartic potential plus a suppressed quadratic one, for which the initial angle, and thus the axion abundance, can be significantly suppressed compared to the quadratic case. we delineate the viable parameter region by taking account of various observational constraints, and find that a broader range of the inflation scale is allowed. also, if the curvature of the potential is suppressed over a certain range of the potential, the onset of coherent oscillations can be delayed. then, the axion dark matter with a small decay constant is possible. we also discuss the π\hspace{-0.2mm}nflation mechanism to realize the hilltop initial condition in the stochastic axion scenario. | stochastic axion dark matter in axion landscape |
we consider the kaluza-klein (kk) graviton and its decays in the presence of the light radion, the modulus of extra dimension, appearing naturally light due to classical scale invariance in warped gravity. due to the presence of a sizable wave function overlap in the extra dimension between the kk graviton and the radion, the kk graviton can decay largely into a pair of radions, each of which decays into a pair of collimated photons or photon-jets. focusing on the setup where the kk graviton has suppressed couplings to the higgs boson and fermions, we discuss the bounds on the light radion in the parameter space where the photon-jets are relevant. moreover, we pursue the possibility of distinguishing the scenario from the case with direct photon contributions by the angular distributions of photons in the lhc run 2. roles of kk graviton and radion as mediators of dark matter interactions, extensions with brane kinetic terms and the model with a holographic composite higgs are also addressed. | kk graviton resonance and cascade decays in warped gravity |
the simplest extension of the standard model by only one real singlet scalar can explain the observed dark matter relic density while giving simultaneously a strongly first-order electroweak phase transition in the early universe. however, after imposing the invisible higgs decay constraint from the lhc, the parameter space of the single scalar model shrinks to regions with only a few percentage of the dm relic abundance and when adding the direct detection bound, e.g. from xenon100, it gets excluded completely. in this paper, we extend the standard model with two real gauge singlet scalars, here s and s', and show that the electroweak symmetry breaking may occur via different channels. despite very restrictive first-order phase transition conditions for the two-scalar model in comparison to the single scalar model, there is a viable space of parameters in different phase transition channels that simultaneously explains a fraction or the whole dark matter relic density, a strongly first-order electroweak phase transition and still evading the direct detection bounds from the latest lux/xenon experiments while respecting the invisible higgs decay width constraint from the lhc. | a simultaneous study of dark matter and phase transition: two-scalar scenario |
a long-standing kinematic challenge in data analysis at hadron colliders is the determination of the masses of invisible particles. this issue is particularly relevant in searches for evidence of dark matter production, which remains one of the prominent targets of future collider experiments. in this paper, we show that the additional information from the precision timing measurements, provided by planned detector upgrades during the high- luminosity run of the lhc (hl-lhc), allows for previously unrealizable measurements of invisible particle kinematics. as a concrete example, we focus on the signal of pair produced long-lived particles (llp1,2), each decaying with a displaced vertex to visible (v1,2) and invisible (i1,2) final state particles, pp → llp1 + llp2→ (v1 + i1) + (v2 + i2). we explicitly show that the complete kinematics of the invisible particles in such events can be determined with the addition of timing information, and evaluate the precision with which the masses of new long-lived and invisible particles can be determined. | timing information at hl-lhc: complete determination of masses of dark matter and long lived particle |
we report a stable magnetic domain wall in a uniform ferromagnetic spin-1 condensate, characterized by the magnetization having a dark soliton profile with nonvanishing superfluid density. we find exact stationary solutions for a particular ratio of interaction parameters with and without magnetic fields, and develop an accurate analytic solution applicable to the whole ferromagnetic phase. in the absence of magnetic fields, this domain wall relates various distinct solitary excitations in binary condensates through so(3 ) spin rotations, which otherwise are unconnected. remarkably, studying the dynamics of a quasi-two-dimensional (quasi-2d) system we show that standing wave excitations of the domain wall oscillate without decay, being stable against the snake instability. the domain wall is dynamically unstable to modes that cause the magnetization to grow perpendicularly while leaving the domain wall unchanged. real-time dynamics in the presence of white noise reveals that this "spin twist" instability does not destroy the topological structure of the magnetic domain wall. | dark-soliton-like magnetic domain walls in a two-dimensional ferromagnetic superfluid |
a review of the higgs portal-vector dark matter interpretation of the spin-independent dark-matter nucleon elastic scattering cross section is presented, where the invisible higgs decay width measured at the lhc is used. effective field theory and ultraviolet complete models are discussed. lhc interpretations show only the scalar and majorana dark-matter scenarios; we propose to include interpretation for vector dark matter in the eft and uv completions theoretical framework. in addition, our studies suggest an extension of the lhc dark matter interpretations to the sub-gev regime. | higgs portal vector dark matter interpretation: review of effective field theory approach and ultraviolet complete models |
the recently proposed trans-planckian censorship conjecture (tcc) amounts to the claim that inflation models with an inflationary energy scale larger than λinfmax ∼109gev belong to the swampland, i.e., cannot be embedded into a consistent theory of quantum gravity. in this paper, we point out that this constraint can be readily satisfied in d-term hybrid inflation (dhi), which is a well-motivated inflation scenario in the context of supersymmetric grand unification. in dhi, the amplitude of the primordial scalar power spectrum originates from a fayet-iliopoulos term of the order of the unification scale, √{ ξ } ∼1016gev. at the same time, the tcc results in an upper bound on the corresponding gauge coupling constant of gmax ∼10-14. we are able to show that this constraint translates into an upper bound on the gravitino mass of m3/2max ∼ 10mev, which opens the possibility that dark matter is accounted for by thermally produced gravitinos, if the reheating temperature is close to treh ∼ 100tev. interestingly enough, a somewhat similar gravitino mass range has recently been derived in a model that aims at explaining dark energy in terms of axion quintessence and resolving the hubble tension by means of decaying gravitino dark matter. | trans-planckian censorship and inflation in grand unified theories |
when the singlet-doublet fermion dark matter model is extended with additional z2-odd real singlet scalars, neutrino masses and mixings can be generated at the one-loop level. in this work, we discuss the salient features arising from the combination of the two resulting simplified dark matter models. when the lightest z2-odd particle is a scalar singlet, br (μ →e γ ) could be measurable provided that the singlet-doublet fermion mixing is small enough. in this scenario, the new decay channels of vector-like fermions into scalars can also generate interesting leptonic plus missing transverse energy signals at the lhc. on the other hand, in the case of doublet-like fermion dark matter, scalar coannihilations lead to an increase in the relic density which allows one to lower the bound of doublet-like fermion dark matter. | radiative neutrino masses in the singlet-doublet fermion dark matter model with scalar singlets |
it has been recently suggested [z. berezhiani, a. d. dolgov, and i. i. tkachev, phys. rev. d 92, 061303 (2015)] that emerging tension between cosmological parameter values derived in high-redshift (cmb anisotropy) and low-redshift (cluster counts, hubble constant) measurements can be reconciled in a model which contains a subdominant fraction of dark matter decaying after recombination. we check the model against the cmb planck data. we find that lensing of the cmb anisotropies by the large-scale structure gives strong extra constraints on this model, limiting the fraction as f <8 % at 2 σ confidence level. however, investigating the combined data set of the cmb and conflicting low-z measurements, we obtain that the model with f ≈2 %- 5 % exhibits better fit (by 1.5 - 3 σ depending on the lensing priors) compared to that of the concordance λ cdm cosmological model. | dark matter component decaying after recombination: lensing constraints with planck data |
mono-x searches are standard dark matter search strategies at the lhc. first, we show how in the case of initial state radiation they essentially collapse to mono-jet searches. second, we systematically study mono-x signatures from decays of heavier dark matter states. direct detection constraints strongly limit our mssm expectations, but largely vanish for mono-z and mono-higgs signals once we include light nmssm mediators. finally, the decay topology motivates mono-w-pair and mono-higgs-pair searches, strengthening and complementing their mono-x counterparts. | actual physics behind mono-x |
we analyzed a 6.7-yr span of data from a rotating torsion-pendulum containing ≈1023 polarized electrons to search for the "wind" arising from ultralight, axionlike dark matter with masses between 10-23 and 10-18 ev /c2 . over much of this range we set a 95% confidence limit fa/ce>2 ×1015 ev on the axionlike decay constant. | constraints on axionlike dark matter with masses down to 10-23 ev /c2 |
in this essay, we discuss the possibilities and associated challenges concerning beyond the standard model searches at fcc-ee, such as rare decays of heavy-flavoured particles and long-lived particles. the standard model contains several suppression mechanisms, which cause a given group of processes to happen rarely, resulting in rare decays. the interest in these decays lies in the fact that the physics beyond the standard model does not need to be affected by the same suppression mechanism and therefore can naturally manifest in these decays. their interest is reinforced by the recent report of several measurements of b-flavoured rare decays, showing deviations with respect to the standard model predictions. we will show how the fcc-ee project has unique capabilities to address these scientific questions and will consider the related detector design challenges to meet. another group of processes discussed are those that produce new particles with relatively long lifetimes that travel substantial distances inside the detectors before decaying. models containing long-lived particles can give answers to many open questions of the standard model, such as the nature of dark matter, or the neutrino masses, among others, while providing an interesting experimental complement to mainstream searches. long-lived particles often display unique experimental signatures, such as displaced tracks and vertices, "disappearing" tracks, or anomalously charged jets. due to this, they are affected by very low background levels but in exchange, they often require dedicated reconstruction algorithms and triggers. the discovery of any of the discussed cases would have a critical impact in high energy physics, and fcc-ee could provide a unique experimental opportunity to explore them. moreover, the searches proposed here could motivate an out-of-the-box optimization of the experimental conditions that could bring in innovative solutions, such as new, possibly very large tracking detectors; or cutting-edge reconstruction algorithms that would boost the fcc-ee reach for unusual final states. | hunt for rare processes and long-lived particles at fcc-ee |
an unidentified line at energy around 3.5 kev was detected in the spectra of dark matter-dominated objects. recent work [1] used 30~msec of xmm-newton blank-sky observations to constrain the admissible line flux, challenging its dark matter decay origin. we demonstrate that these bounds are overestimated by more than an order of magnitude due to improper background modeling. therefore, the dark matter interpretation of the 3.5~kev signal remains viable. | technical comment on the paper of dessert et al. "the dark matter interpretation of the 3.5 kev line is inconsistent with blank-sky observations" |
to address the link between the composition and decomposition of freshwater dissolved organic matter (dom), we manipulated the dom from three boreal lakes using preincubations with uv light to cleave large aromatic molecules and polyvinylpyrrolidone (pvp) to remove colored phenolic compounds. subsequently, we monitored the dissolved organic carbon (doc) loss over 4 months of microbial degradation in the dark to assess how compositional changes in dom affected different aspects of the reactivity continuum, including the distribution of the apparent decay coefficients. we observed profound effects on decomposition kinetics, with pronounced shifts in the relative share of rapidly and more slowly decomposing fractions of the dom. in the uv-exposed treatment initial apparent decay coefficient k0 was almost threefold higher than in the control. significantly higher relative doc loss in the uv-exposed treatment was sustained for 2 months of incubation, after which decay coefficients converged with those in the control. the pvp removed compounds with absorbance and fluorescence characteristics representative of aromatic compounds, which led to slower decomposition, compared to that in the control. our results demonstrate the reactivity continuum underlying the decomposition of dom in freshwaters and highlight the importance of intrinsic properties of dom in determining its decomposition kinetics. | effects of compositional changes on reactivity continuum and decomposition kinetics of lake dissolved organic matter |
we generalize dark matter production to a two-metric framework whereby the physical metric, which couples to the standard model (sm), is conformally and/or disformally related to the metric governing the gravitational dynamics. we show that this setup is naturally present in many ultra violet (uv) constructions, from kähler moduli fields to tensor-portal models, and from emergent gravity to supergravity models. in this setting we study dark matter production in the early universe resulting from both scatterings off the thermal bath and the radiative decay of the inflaton. we also take into account noninstantaneous reheating effects at the end of inflation. in this context, dark matter emerges from the production of the scalar field mediating the conformal/disformal interactions with the sm, i.e., realizing a feebly interacting matter particle (fimp) scenario where the suppression scale of the interaction between the scalar and the sm can be taken almost as high as the planck scale in the deep uv. | disformal dark matter |
recent investigations have emphasized the importance of uncertainty quantification (uq) in nuclear theory. we carry out uq for configuration-interaction shell-model calculations in the 1 s -0 d valence space, investigating the sensitivity of observables to perturbations in the 66 parameters (matrix elements) of a high-quality empirical interaction. the large parameter space makes computing the corresponding hessian numerically costly, so we compare a cost-effective approximation, using the feynman-hellmann theorem, to the full hessian and find it works well. diagonalizing the hessian yields the principal components of the interaction: linear combinations of parameters ordered by sensitivity. this approximately decoupled distribution of parameters facilitates theoretical uncertainty propagation onto structure observables: electromagnetic transitions, gamow-teller decays, and dark matter-nucleus scattering matrix elements. | uncertainty quantification of an empirical shell-model interaction using principal component analysis |
strong coupling between quantum emitters and photonic modes, at which the level splitting (ls) of the mixed quantum states occurs, has aroused great interest due to diverse important quantum applications. the spectral rabi-splitting (srs) in photon emission or absorption has been extensively used to characterize strong coupling based on the equality assumption by assigning the srs to ls. here, we demonstrate that the equality assumption is usually invalid via a unified quantum treatment on the coupled plasmon-exciton system. it is revealed that the strong coupling characterized by the srs is easily observed from the subsystem with larger decay, manifesting itself in relativity and diversity, which is highly correlated to the dissipative decays of the coupling subsystems. the plasmon-exciton interactions can be classified into the weak coupling, pseudo-, dark-, intermediate- and super-strong coupling regimes. our work not only enriches the underlying physics of strong light-matter interactions, but also may stimulate further experimental researches in this field. | relativity and diversity of strong coupling in coupled plasmon-exciton systems |
the residual radioactive contaminations of zinc tungstate crystal scintillators, produced by low-thermal-gradient czochralski technique in various conditions, have been measured in the dama/r&d low background setup at the gran sasso national laboratory (infn, italy). the total alpha activity has been measured in the detectors realized with different processes to vary between 158 and 1418 μbq/kg. the internal 228th contamination activity has been estimated as 0.34 μbq/kg in the most polluted crystal, while only upper limits for other ones have been set at level from < 0.17 μbq/kg to < 1.3 μbq/kg. these results open possibility for further radio-purifications of znwo4 crystal scintillators, which are of potential interests in various fields. | new development of radiopure znwo4 crystal scintillators |
we have developed and tested a new way of coupling bolometric light detectors to scintillating crystal bolometers based upon simply resting the light detector on the crystal surface, held in position only by gravity. this straightforward mounting results in three important improvements: (1) it decreases the amount of non-active materials needed to assemble the detector, (2) it substantially increases the light collection efficiency by minimizing the light losses induced by the mounting structure, (3) and it enhances the thermal signal induced in the light detector thanks to the extremely weak thermal link to the thermal bath. we tested this new technique with a 16 cm2 ge light detector with thermistor readout sitting on the surface of a large teo2 bolometer. the light collection efficiency was increased by greater than 50% compared to previously tested alternative mountings. we obtained a baseline energy resolution on the light detector of 20 ev rms that, together with increased light collection, enabled us to obtain the best α vs β / γ discrimination ever obtained with massive teo2 crystals. at the same time we achieved rise and decay times of 0.8 and 1.6 ms, respectively. this superb performance meets all of the requirements for the cupid (cuore upgrade with particle identification) experiment, which is a 1-ton scintillating bolometer follow up to cuore. | cryogenic light detectors with enhanced performance for rare event physics |
we investigate the possibility that the peccei-quinn phase transition occurs at a temperature far below the symmetry breaking scale. low phase transition temperatures are typical in supersymmetric theories, where symmetry breaking fields have small masses. we find that qcd axions are abundantly produced just after the phase transition. the observed dark matter abundance is reproduced even if the decay constant is much lower than 1011 gev. the produced axions tend to be warm. for some range of the decay constant, the effect of the predicted warmness on structure formation can be confirmed by future observations of 21 cm lines. a portion of parameter space requires a mixing between the peccei-quinn symmetry breaking field and the standard model higgs, and predicts an observable rate of rare kaon decays. | qcd axion dark matter from a late time phase transition |
discrepancies from in-beam- and in-bottle-type experiments measuring the neutron lifetime are on the 4 σ standard deviation level. in a recent publication fornal and grinstein proposed that the puzzle could be solved if the neutron would decay on the one percent level via a dark decay mode, one possible branch being n →χ +e+e-. with data from the perkeo ii experiment we set limits on the branching fraction and exclude a one percent contribution for 95% of the allowed mass range for the dark matter particle. | constraints on the dark matter interpretation n →χ +e+e- of the neutron decay anomaly with the perkeo ii experiment |
we present the results of the search for decaying dark matter with particle mass in the 6-40 kev range with nustar deep observations of cosmos and ecdfs empty sky fields. we show that the main contribution to the decaying dark matter signal from the milky way galaxy comes through the aperture of the nustar detector, rather than through the focusing optics. the high sensitivity of the nustar detector, combined with the large aperture and large exposure times of the two observation fields, allows us to improve previously existing constraints on the dark matter decay time by up to an order of magnitude in the mass range 10-30 kev. in the particular case of the ν msm sterile neutrino dark matter, our constraints impose an upper bound m <20 kev on the dark matter particle mass. we report detection of four unidentified spectral lines (including the line at 3.51 kev) in our data set. these line detections are either due to the systematic effects (uncertainties of calibrations of the nustar detectors) or have an astrophysical origin. we discuss different possibilities for testing the nature of the detected lines. | decaying dark matter search with nustar deep sky observations |
cosmological relaxation of the electroweak scale via higgs-axion interplay, named as relaxion mechanism, provides a dynamical solution to the higgs mass hierarchy. in the original proposal by graham, kaplan and rajendran, the relaxion abundance today is too small to explain the dark matter of the universe because of the high suppression of the misalignment angle after inflation. it was then realised by banerjee, kim and perez that reheating effects can displace the relaxion, thus enabling it to account for the dark matter abundance from the misalignment mechanism. however, this scenario is realised in a limited region of parameter space to avoid runaway. we show that in the regime where inflationary fluctuations dominate over the classical slow-roll, the "stochastic misalignment" of the field due to fluctuations can be large. we study the evolution of the relaxion after inflation, including the high-temperature scenario, in which the barriers of the potential shrink and destabilise temporarily the local minimum. we open new regions of parameter space where the relaxion can naturally explain the observed dark matter density in the universe, towards larger coupling, larger mass, larger mixing angle, smaller decay constant, as well as larger scale of inflation. | relaxion dark matter from stochastic misalignment |
oscillons are localized states of scalar fields sustained by self interactions. they decay by emitting classical radiation, but their lifetimes are surprisingly large. we revisit the reasons behind their longevity, aiming at how the shape of the scalar potential v(ϕ) determines the lifetime. the corpuscular picture, where the oscillon is identified with a bound state of a large number of field quanta, allows to understand lifetimes of order of 103 cycles in generic potentials. at the non-perturbative level, two properties of the scalar potential can substantially boost the lifetime: the flattening of v(ϕ) and the positivity of v"(ϕ). these properties are realized in the axion monodromy family of potentials. moreover, this class of models connects continuously with an exceptional potential that admits eternal oscillon solutions. we check these results with a new fast-forward numerical method that allows to evolve in time to stages that cannot be otherwise simulated on a computer. the method exploits the attractor properties of the oscillons and fully accounts for nonlinearities. we find lifetimes up to 1014 cycles, but larger values are possible. our work shows that oscillons formed in the early universe can be stable on cosmological time scales and thus contribute to the abundance of (ultra)light scalar dark matter. | recipes for oscillon longevity |
a new mechanism has been proposed to simultaneously explain the presence of dark matter and the matter-antimatter asymmetry in the universe. this scenario predicts exotic b -meson decays into a baryon and a dark-sector antibaryon (ψd) with branching fractions accessible at b factories. we present a search for b →λ ψd decays using data collected by the babar experiment at slac. this reaction is identified by fully reconstructing the accompanying b meson and requiring the presence of a single λ baryon in the remaining particles. no significant signal is observed, and bounds on the b →λ ψd branching fraction are derived in the range 0.13 - 5.2 ×10-5 for 1.0 <mψ d<4.2 gev /c2 . these results set strong constraints on the parameter space allowed by the theory. | search for b mesogenesis at babar |
we review the current status of the long-term programme of numerical investigation of sp(2n) gauge theories with and without fermionic matter content. we start by introducing the phenomenological as well as theoretical motivations for this research programme, which are related to composite higgs models, models of partial top compositeness, dark matter models, and in general to the physics of strongly coupled theories and their approach to the large-n limit. we summarise the results of lattice studies conducted so far in the sp(2n) yang–mills theories, measuring the string tension, the mass spectrum of glueballs and the topological susceptibility, and discuss their large-n extrapolation. we then focus our discussion on sp(4), and summarise the numerical measurements of mass and decay constant of mesons in the theories with fermion matter in either the fundamental or the antisymmetric representation, first in the quenched approximation, and then with dynamical fermions. we finally discuss the case of dynamical fermions in mixed representations, and exotic composite fermion states such as the chimera baryons. we conclude by sketching the future stages of the programme. we also describe our approach to open access. | sp(2n) lattice gauge theories and extensions of the standard model of particle physics |
a search for dark matter produced in association with a higgs boson in final states with two hadronically decaying $\tau$-leptons and missing transverse momentum is presented. the analysis uses $139$ fb$^{-1}$ of proton-proton collision data at $\sqrt{s}=13$ tev collected by the atlas experiment at the large hadron collider between 2015 and 2018. no evidence for physics beyond the standard model is found. the results are interpreted in terms of a 2hdm+$a$ model. exclusion limits at 95% confidence level are derived. model-independent limits are also set on the visible cross section for processes beyond the standard model producing missing transverse momentum in association with a higgs boson decaying to $\tau$-leptons. | search for dark matter produced in association with a higgs boson decaying to tau leptons at $\\sqrt{s}=13$ tev with the atlas detector |
in the context of twin higgs models, we study a simple mechanism that simultaneously generates asymmetries in the dark and visible sector through the out-of-equilibrium decay of a tev-scale particle charged under a combination of baryon and twin baryon number. we predict the dark matter to be a 5 gev twin baryon, which is easy to achieve because of the similarity between the two confinement scales. dark matter is metastable and can decay to three quarks, yielding indirect detection signatures. the mechanism requires the introduction of a new colored particle, typically within the reach of the lhc, of which we study the rich collider phenomenology, including prompt and displaced dijets, multijets, monojets and monotops. | twin mechanism for baryon and dark matter asymmetries |
the discovery by the icecube experiment of a high-energy astrophysical neutrino flux with energies of the order of pev, has opened new scenarios in astroparticles physics. a possibility to explain this phenomenon is to consider the minimal models of dark matter (dm) decay, the 4-dimensional operator ∼ y_{α χ }\overline{{l_{l_{α }}}} h χ , which is also able to generate the correct abundance of dm in the universe. assuming that the cosmological background evolves according to the standard cosmological model, it follows that the rate of dm decay γ _χ ∼ |y_{α χ }|^2 needed to get the correct dm relic abundance (γ _χ ∼ 10^{-58}) differs by many orders of magnitude with respect that one needed to explain the icecube data (γ _χ ∼ 10^{-25}), making the four-dimensional operator unsuitable. in this paper we show that assuming that the early universe evolution is governed by a modified cosmology, the discrepancy between the two the dm decay rates can be reconciled, and both the icecube neutrino rate and relic density can be explained in a minimal model. | pev icecube signals and dark matter relic abundance in modified cosmologies |
the axion mass receives a large correction from small instantons if the qcd gets strongly coupled at high energies. we discuss the size of the new cp violating phases caused by the fact that the small instantons are sensitive to the uv physics. we also discuss the effects of the mass correction on the axion abundance of the universe. taking the small-instanton contributions into account, we propose a natural scenario of axion dark matter where the axion decay constant is as large as 1015-16 gev. the scenario works in the high-scale inflation models. | strong cp problem and axion dark matter with small instantons |
the domain wall problem of the peccei-quinn mechanism can be solved if the peccei-quinn symmetry is explicitly broken by a small amount. domain walls decay into axions, which may account for dark matter of the universe. this scheme is however strongly constrained by overproduction of axions unless the phase of the explicit breaking term is tuned. we investigate the case where the universe is matter-dominated around the temperature of the mev scale and domain walls decay during this matter dominated epoch. we show how the viable parameter space is expanded. | qcd axion dark matter from long-lived domain walls during matter domination |
we propose probing sub-gev dark photon decays into lighter dark matter using monophoton events at the besiii detector and future super tau charm factory (stcf). we compute the cross section due to the dark photon associated a standard model photon production, and study the corresponding standard model irreducible/reducible backgrounds. by using the luminosity about 14 fb-1 collected at the besiii detector since 2012, we derive new expected leading limits of the mixing strength ɛ , ɛ ≲(1.3 -1.7 )×10-4, in the mass range of 0.04 gev ≲ma'≲3 gev . with the luminosity of 30 ab-1 , stcf running at √{s }=2 gev , can probe ɛ down to 5.1 ×10-6 when ma'=1 gev . for models of scalar and fermionic light thermal dark matter production via dark photon, we present the constrains on the dimensionless dark matter parameter y =ɛ2αd(mχ/ma')4 as function of the dm mass mχ at besiii and future stcf, conventionally assuming the dark coupling constant αd=0.5 and ma'=3 mχ. we find that besiii can exclude models of scalar, majorana, and pseudo-dirac (with a small splitting) dm for the mass region 0.04-1 gev, 0.05-1 gev and 0.4-1 gev respectively. for values αd≲0.005 , combining the results from 2 gev stcf with the luminosity of 30 ab-1 and babar, one can exclude the above three dm models in the mass region 0.001 gev ≲mχ≲1 gev . | probing invisible decay of a dark photon at besiii and a future super tau charm factory via monophoton searches |
it has been proposed that two resonances could coincide in the early universe at temperatures t ~ 0.2 ... 0.5 gev: one between two nearly degenerate gev-scale sterile neutrinos, producing a large lepton asymmetry through freeze-out and decays; another between medium-modified active neutrinos and kev-scale sterile neutrinos, converting the lepton asymmetry into dark matter. making use of a framework which tracks three sterile neutrinos of both helicities as well as three separate lepton asymmetries, and scanning the parameter space of the gev-scale species, we establish the degree of fine-tuning that is needed for realizing this scenario. | sterile neutrino dark matter via coinciding resonances |
it has long been known that the sharpened tension between the observed and inferred values of the hubble constant h0 can be alleviated if a fraction of dark-matter particles of type χ were produced nonthermally in association with photons γ through the decays of a heavy and relatively long-lived state, viz., x →χ γ . it was recently proposed that this model can also resolve the long-standing lithium (also known as li 7 ) problem if m =4 mev and m =0.04 kev , where m and m are, respectively, the masses of x and χ . we confront this proposal with experiment and demonstrate that cold dark matter decaying before recombination cannot resolve the h0 problem. moreover, we show that the best-case scenario for alleviating the h0 tension within the context of cold dark matter decaying before recombination arises when the particles decay exclusively into dark radiation, while leaving completely unmodified the production of light elements. to this end, we calculate the general functional form describing the number of equivalent light neutrino species δ neff carried by χ . we show that to resolve the h0 tension at the 1 σ level, a 55% correction in m is needed and that the required δ neff is excluded at 95% c.l. by planck data. we argue in favor of a more complex model of dynamical dark matter to relax the h0 tension. | decaying dark matter, the h0 tension, and the lithium problem |
we revisit a mechanism to enhance the decay width of (pseudo-)scalar resonances to photon pairs when the process is mediated by loops of charged fermions produced near threshold. motivated by the recent lhc data, indicating the presence of an excess in the diphoton spectrum at approximately 750 gev, we illustrate this threshold enhancement mechanism in the case of a 750 gev pseudoscalar boson a with a two-photon decay mediated by a charged and uncolored fermion having a mass at the 1/2ma threshold and a small decay width, < 1 mev. the implications of such a threshold enhancement are discussed in two explicit scenarios: i) the minimal supersymmetric standard model in which the a state is produced via the top quark mediated gluon fusion process and decays into photons predominantly through loops of charginos with masses close to 1/2ma and ii) a two higgs doublet model in which a is again produced by gluon fusion but decays into photons through loops of vector-like charged heavy leptons. in both these scenarios, while the mass of the charged fermion has to be adjusted to be extremely close to half of the a resonance mass, the small total widths are naturally obtained if only suppressed three-body decay channels occur. finally, the implications of some of these scenarios for dark matter are discussed. | threshold enhancement of diphoton resonances |
in this rapid communication, we address the chiral properties of valley exciton-polaritons in a monolayer of w s2 in the regime of strong light-matter coupling with a tamm-plasmon resonance. we observe that the effect of valley polarization, which manifests in the circular polarization of the emitted photoluminescence as the sample is driven by a circularly polarized laser, is strongly enhanced in comparison to bare w s2 monolayers and can even be observed under strongly nonresonant excitation at ambient conditions. in order to explain this effect in more detail, we study the relaxation and decay dynamics of exciton-polaritons in our device, elaborate the role of the dark state, and present a microscopic model to explain the wave-vector-dependent valley depolarization by the linear polarization splitting inherent to the microcavity. we believe that our findings are crucial for designing novel polariton-valleytronic devices which can be operated at room temperature. | observation of macroscopic valley-polarized monolayer exciton-polaritons at room temperature |
we study the early kinetic decoupling effect in a pseudo-nambu-goldstone (png) dark matter (dm) model. the png dm scattering processes with particles in the thermal bath in the early universe are suppressed by the small momentum transfer. as a result, kinetic equilibrium is not maintained, and the temperature of dm is different from the temperature of the thermal bath at the freeze-out era. this temperature difference affects the thermal relic abundance of dm. we investigate the early kinetic decoupling in the higgs resonance region, 50 gev ≲mχ≲mh/2 , where mχ is the mass of the dm, and mh/2 ≃62.5 gev . we find that the dm-higgs coupling determined to obtain the measured value of the dm energy density is underestimated in the literature. the enhancement in the coupling leads larger value of the higgs invisible decay rate. it enlarges the capability to discover the dm signals from the decay of the higgs bosons at collider experiments. | early kinetic decoupling and a pseudo-nambu-goldstone dark matter model |
if a fraction fdcdm of the dark matter decays into invisible and massless particles (so-called "dark radiation") with the decay rate (or inverse lifetime) γdcdm, such decay will leave distinctive imprints on cosmological observables. with a full consideration of the boltzmann hierarchy, we calculate the decay-induced impacts not only on the cmb but also on the redshift distortion and the kinetic sunyaev-zel'dovich effect, while providing detailed physical interpretations based on evaluating the evolution of gravitational potential. by using the current cosmological data with a combination of planck 2015, baryon acoustic oscillation and redshift distortion measurements which can improve the constraints, we update the 1σ bound on the fraction of decaying dm from fdcdmlesssim5.26% to fdcdmlesssim2.73% for the short-lived dm (assuming γdcdm/h0gtrsim104). however, no constraints are improved from rsd data (fdcdmlesssim0.94%) for the long-lived dm (i.e., γdcdm/h0lesssim104). we also find the fractional dm decay can only slightly reduce the h0 and σ8 tensions, which is consistent with other previous works. furthermore, our calculations show that the ksz effect in future would provide a further constraining power on the decaying dm. | fractional dark matter decay: cosmological imprints and observational constraints |
pandax-4t is a ton-scale dark matter direct detection experiment using a dual-phase tpc technique at the china jinping underground laboratory. various ultra-low background technologies have been developed and applied to material screening for pandax-4t, including hpge gamma spectroscopy, icp-ms, naa, radon emanation measurement system, krypton assay station, and alpha detection system. low background materials were selected to assemble the detector. surface treatment procedures were investigated to further suppress radioactive background. combining measured results and monte carlo simulation, the total material background rates of pandax-4t in the energy region of 1-25 kevee are estimated to be (9.9 ± 1.9) × 10-3 mdru for electron recoil and (2.8 ± 0.6) × 10-4 mdru for nuclear recoil. in addition, natkr in the detector is estimated to be < 8 ppt. | low radioactive material screening and background control for the pandax-4t experiment |
the origin of neutrino flux observed in icecube is still mainly unknown. typically two flux components are assumed, namely: atmospheric neutrinos and an unknown astrophysical term. in principle the latter could also contain a top-down contribution coming for example from decaying dark matter. in this case one should also expect prompt and secondary gamma's as well. this leads to the possibility of a multimessenger analysis based on the simultaneous comparison of the dark matter hypothesis both with neutrino and high energy gamma rays data. in this paper, we analyze, for different decaying dark matter channels, the 7.5 years icecube hese data, and compare the results with previous exclusion limits coming from fermi data. finally, we test whether the dark matter hypothesis could be further scrutinised by using forthcoming high energy gamma rays experiments. | decaying dark matter at icecube and its signature on high energy gamma experiments |
it has been found that a pseudo-nambu-goldstone boson dark matter suppresses the amplitude for elastic scattering with nuclei in non-relativistic limit, and thus can naturally evade the strong constraint of dark matter direct detection experiments. in this paper, we show that non-zero elastic scattering cross section can be induced if the mediator mass is as small as momentum transfer. the predicted recoil energy spectrum can differ from that for usual thermal dark matter. together with the relevant constraints such as thermal relic abundance, indirect detection and higgs decays, we investigate the detectability through the current and future dark matter direct detection experiments. | direct detection of pseudo-nambu-goldstone dark matter with light mediator |
we introduce and study the first class of signals that can probe the dark matter in mesogenesis which will be observable at current and upcoming large volume neutrino experiments. the well-motivated mesogenesis scenario for generating the observed matter-anti-matter asymmetry necessarily has dark matter charged under baryon number. interactions of these particles with nuclei can induce nucleon decay with kinematics differing from sponanteous nucleon decay. we calculate the rate for this process and develop a simulation of the signal that includes important distortions due to nuclear effects. we estimate the sensitivity of dune, super-kamiokande, and hyper-kamiokande to this striking signal. | dark matter induced nucleon decay signals in mesogenesis |
a search for a narrow resonance with a mass between 350 and 700 gev, and decaying into a pair of jets, is performed using proton-proton collision events containing at least three jets. the data sample corresponds to an integrated luminosity of 18.3 fb$^{-1}$ recorded at $\sqrt{s} =$ 13 tev with the cms detector. data are collected with a technique known as "data scouting", in which the events are reconstructed, selected, and recorded at a high rate in a compact form by the high-level trigger. the three-jet final state provides sensitivity to lower resonance masses than in previous searches using the data scouting technique. the spectrum of the dijet invariant mass, calculated from the two jets with the largest transverse momenta in the event, is used to search for a resonance. no significant excess over a smoothly falling background is found. limits at 95% confidence level are set on the production cross section of a narrow dijet resonance and compared with the cross section of a vector dark matter mediator coupling to dark matter particles and quarks. translating to a model where the narrow vector resonance interacts only with quarks, upper limits on this coupling range between 0.10 and 0.15, depending on the resonance mass. these results represent the most stringent upper limits in the mass range between 350 and 450 gev obtained with a flavor-inclusive dijet resonance search. | search for dijet resonances using events with three jets in proton-proton collisions at $\\sqrt{s} =$ 13 tev |
we explore the prospects for observing cp violation in the minimal supersymmetric extension of the standard model (mssm) with six cp-violating parameters, three gaugino mass phases and three phases in trilinear soft supersymmetry-breaking parameters, using the cpsuperh code combined with a geometric approach to maximise cp-violating observables subject to the experimental upper bounds on electric dipole moments. we also implement cp-conserving constraints from higgs physics, flavour physics and the upper limits on the cosmological dark matter density and spin-independent scattering. we study possible values of observables within the constrained mssm (cmssm), the non-universal higgs model (nuhm), the cpx scenario and a variant of the phenomenological mssm (pmssm). we find values of the cp-violating asymmetry in decay that may be as large as 3 %, so future measurements of may provide independent information about cp violation in the mssm. we find that cp-violating mssm contributions to the meson mass mixing term are in general below the present upper limit, which is dominated by theoretical uncertainties. if these could be reduced, could also provide an interesting and complementary constraint on the six cp-violating mssm phases, enabling them all to be determined experimentally, in principle. we also find that cp violation in the and couplings can be quite large, and so may offer interesting prospects for future , , and colliders. | exploring cp violation in the mssm |
anomaly-mediated supersymmetry breaking (amsb) models seem to have become increasingly implausible due to 1) difficulty in generating a higgs mass mh∼125 gev , 2) typically unnatural superparticle spectra characterized by a large superpotential mu term, and 3) the possibility of a winolike lightest supersymmetry particle as dark matter now seems to be excluded. in the present paper, we propose some modifications to the paradigm model which solve these three issues. instead of adding a universal bulk scalar mass to avoid tachyonic sleptons, we add distinct higgs and matter scalar soft masses which then allow for light higgsinos. to gain accord with the measured higgs mass, we also include a bulk trilinear soft term. the ensuing natural generalized amsb model then has a set of light higgsinos with mass nearby the weak scale m (w ,z ,h )∼100 gev as required by naturalness, while the winos populate the several hundred gev range and gluinos and squarks occupy the multi-tev range. for lhc searches, the wino pair production followed by decay to the same-sign diboson signature channel offers excellent prospects for discovery at the high luminosity lhc along with higgsino pair production leading to soft dileptons plus jet (s )+met . a linear e+e- collider operating above the higgsino pair production threshold should be able to distinguish the amsb gaugino spectra from unified or mirage unified scenarios. dark matter is expected to occur as a higgsino-like weakly interacting massive particle plus axion admixture. | anomaly-mediated susy breaking model retrofitted for naturalness |
we consider an anomaly-free u(1) extension of the standard model with three right-handed neutrinos (rhns) and two complex scalars, wherein the charge assignments preclude all tree-level mass terms for the neutrinos. considering this setup, in turn, to be only a low-energy effective theory, we introduce higher-dimensional terms a la froggatt-nielsen to naturally generate tiny neutrino masses. one of the rhns turns out to be very light, thereby constituting the main decay mode for the z' and hence relaxing the lhc dilepton resonance search constraints. the lightest rhn has a lifetime comparable to or bigger than the age of the universe, and, hence, could account for a non-negligible fraction of the dark matter. | neutrino and z' phenomenology in an anomaly-free u(1) extension: role of higher-dimensional operators |
we investigate whether the recently observed 2.6 m ⊙ compact object in the gravitational wave event gw190814 can be a bosonic dark matter (dm) admixed compact star. by considering the three constraints of mass, radius, and the stability of such an object, we find that if the dm is made of qcd axions, their particle mass m is constrained to a range that has already been ruled out by the independent constraint imposed by the stellar-mass black hole superradiance process. the 2.6 m ⊙ object can still be a neutron star admixed with at least 2.0 m ⊙ of dm made of axion-like particles (or even a pure axion-like particle star) if 2 × 10-11 ev ≤ m ≤ 2.4 × 10-11 ev (2.9 × 10-11 ev ≤ m ≤ 3.2 × 10-11 ev) with a decay constant of f ≥ 8 × 1017 gev. | could the gw190814 secondary component be a bosonic dark matter admixed compact star? |
we present a model explaining both the 4.2 σ muon g -2 anomaly and the relic density of dark matter (dm) in which dm interacts with the standard model (sm) via a scalar portal boson φ carrying both dark and sm leptonic numbers, and mediating a nondiagonal interaction between the electron and muon that allows e ↔μ transitions. the φ could be produced in high-energy electron scattering off a target nuclei in the reaction e z →μ z φ followed by the prompt invisible decay φ →dm particles and searched for in events with large missing energy accompanied by a single outgoing muon in the final state. interestingly, several events with a similar signature have been observed in a data sample of ≃3 ×1011 electrons on target collected during 2016-2018 for the search for light dark matter in the na64 experiment at the cern sps [d. banerjee et al. (na64 collaboration), phys. rev. lett. 123, 121801 (2019)., 10.1103/physrevlett.123.121801]. attributing so far these events to background allows us to set first constraints on the φ mass and couplings while leaving at the same time decisively probing the origin of these events and a large fraction of the remaining parameter space to a near exiting future with the upgraded na64 detector or other planned experiments. | leptonic scalar portal: origin of muon g -2 anomaly and dark matter? |
in this paper, we discuss interesting scenarios resulting from the interplay between the gravitino and the lightest right-handed (s)neutrino. we consider two gravitino mass regimes vastly separated, that is, m3/2 = o (100) ev and m3/2 ≃ 100 gev. for the former case, a significant amount of the entropy production in the cosmological history to dilute the gravitino relic abundance is unavoidable for consistency with the number of satellite galaxies in the milky way. we will show that the right-handed (s)neutrino can play the role of the heavy particle whose late time decay provides such an additional radiation. for the later case, the gravitino of m3/2 ≃ 100 gev may resolve the s8 tension as a decaying dark matter. we will show how the lightest right-handed neutrino and its superpartner can help the gravitino decaying dark matter be equipped with a long enough life time and mass degeneracy with a massive decay product to address the s8 tension. | gravitino cosmology helped by a right handed (s)neutrino |
we present a thorough discussion of light dark matter produced via freeze-in in two-body decays a→ b dm . if a and b are quasi-degenerate, the dark matter particle has a cold spectrum even for kev masses. we show this explicitly by calculating the transfer function that encodes the impact on structure formation. as examples for this setup we study extended seesaw mechanisms with a spontaneously broken global u(1) symmetry, such as the inverse seesaw. the kev-scale pseudo-goldstone dark matter particle is then naturally produced cold by the decays of the quasi-degenerate right-handed neutrinos. | cold light dark matter in extended seesaw models |
the dama collaboration reported an annually modulated rate with a phase compatible with a dark matter induced signal. we point out that a slowly varying rate can bias or even simulate an annual modulation if data are analyzed in terms of residuals computed by subtracting approximately yearly averages starting from a fixed date, rather than a background continuous in time. in the most extreme case, the amplitude and phase of the annual modulation reported by dama could be alternatively interpreted as a decennial growth of the rate. this possibility appears mildly disfavoured by a detailed study of the available data, but cannot be safely excluded. in general, a decreasing or increasing rate could partially reduce or enhance a true annual modulation, respectively. the issue could be clarified by looking at the full time-dependence of the dama total rate, not explicitly published so far. | annual modulations from secular variations: relaxing dama? |
we present a minimal uv complete framework to embed inflation and dark matter by extending the standard model with a singlet real scalar field (the inflaton) and a singlet fermionic field acting as dark matter. the inflaton features the most general renormalizable polynomial up to quartic order, which is flat due to the existence of a perturbed inflection-point, comfortably fitting cmb measurements. we also analyze (p)reheating by considering the higgs production via inflaton decay. in the early universe, dark matter can be generated by the mediation of gravitons or inflatons. however, the production via the direct decay of the inflatons dominates, making viable a large range of dark matter masses, from o (10-5) gev to o (1011) gev. | polynomial inflation and dark matter |
we study polariton superregular (sr) breathers triggered by the resonant interaction of an optical field with two-level doping ions in an erbium-doped fiber. we demonstrate explicitly that the optical wave component always features a bright structure that describes the modulation instability (mi) development from localized small perturbations, while the sr matter-wave breathers exhibit more complicated dynamical evolution, which are absent in standard scalar sr breather theory. despite the complexity, the exact link between these sr breathers and mi is established strictly by showing that the absolute difference of group velocities of sr breathers coincides exactly with the linear mi growth rate. in particular, we show how a small dip perturbation of the dark sr breather in the matter wave component induces an intriguing mi process of completely exponential decay. these results will enrich our understanding on the mi development in complex coupled light-matter interaction systems. | polariton superregular breathers in a resonant erbium-doped fiber |
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