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we study the role of the standard model higgs condensate, formed during cosmological inflation, in the epoch of reheating that follows. we focus on the scenario where the inflaton decays slowly and perturbatively, so that there is a long period between the end of inflation and the beginning of radiation domination. the higgs condensate decays nonperturbatively during this period, and we show that it heats the primordial plasma to much higher temperatures than would result from the slowly decaying inflaton alone. we discuss the effect of this hot plasma on the thermalization of the inflaton's decay products, and study its phenomenological implications for the formation of cosmological relics like dark matter, with associated isocurvature fluctuations, and the restoration of the electroweak and peccei-quinn symmetries. | achieving the highest temperature during reheating with the higgs condensate |
we explore experimentally a quantum metamaterial based on a superconducting chip with 25 frequency-tunable transmon qubits coupled to a common coplanar resonator. the collective bright and dark modes are probed via the microwave response, i.e., by measuring the transmission amplitude of an external microwave signal. all qubits have individual control and readout lines. their frequency tunability allows the number n of resonantly coupled qubits to change and a disorder in their excitation frequencies to be introduced with preassigned distributions. while increasing n , we demonstrate the expected n1 /2 scaling law for the energy gap (rabi splitting) between bright modes around the cavity frequency. by introducing a controllable disorder and averaging the transmission amplitude over a large number of realizations, we demonstrate a decay of mesoscopic fluctuations which mimics an approach towards the thermodynamic limit. the collective bright states survive in the presence of disorder when the strength of individual qubit coupling to the cavity dominates over the disorder strength. | cavity-qed simulation of a quantum metamaterial with tunable disorder |
we study radiative plateaulike inflation and zb l -portal freeze-in fermionic dark matter in a minimal b -l extended model. the u(1 ) b -l higgs, responsible for heavy neutrino masses, also drives inflation in the early universe, thanks to radiative corrections from the heavy neutrinos and the zb l gauge boson. in our benchmark choice for the u(1 ) b -l gauge coupling gb -l∼10-4, a light zb l boson can be explored by current and future lifetime frontier experiments, such as the forward search experiment (faser) and faser 2 at the lhc, ship, belle ii, and lhcb. for the benchmark, the hubble scale of inflation (hinf) is very low [hinf=o (100 ) ev ] and the inflaton turns out to be very light with mass of o (1 ) ev , and consequently the decay width of the inflaton is extremely small. we investigate a two-field system with the inflaton /b -l higgs and the standard model (sm) higgs, and find that the reheating with a sufficiently high temperature occurs when the waterfall direction to the sm higgs direction opens up in the trajectory of the scalar field evolution. | ev hubble scale inflation with a radiative plateau: very light inflaton, reheating, and dark matter in b -l extensions |
in the standard model (sm) of particle physics, the branching ratio for higgs boson decays to a final state which is invisible to collider detectors, $h \rightarrow zz^{\star} \rightarrow \nu \bar{\nu} \nu \bar{\nu}$, is order 0.10%. in theories beyond the sm (bsm), this branching ratio can be enhanced by decays to undiscovered particles like dark matter (dm). at the large hadron collider (lhc), the current best upper limit on the branching ratio of invisible higgs boson decays is 11% at 95% confidence level. we investigate the expected sensitivity to invisible higgs decays with the silicon detector (sid) at the international linear collider (ilc). we conclude that at $\sqrt{s}=250$ gev with 900 fb$^{-1}$ integrated luminosity each for $e_{l}^-e_{r}^+$ and $e_{r}^-e_{l}^+$ at nominal beam polarization fractions, the expected upper limit is 0.16% at 95% confidence level. | expected sensitivity to invisible higgs boson decays at the ilc with the sid detector (a snowmass white paper) |
weakly-coupled tev-scale particles may mediate the interactions between normal matter and dark matter. if so, the lhc would produce dark matter through these mediators, leading to the familiar "mono- x" search signatures, but the mediators would also produce signals without missing momentum via the same vertices involved in their production. this document from the lhc dark matter working group suggests how to compare searches for these two types of signals in case of vector and axial-vector mediators, based on a workshop that took place on september 19/20, 2016 and subsequent discussions. these suggestions include how to extend the spin-1 mediated simplified models already in widespread use to include lepton couplings. this document also provides analytic calculations of the relic density in the simplified models and reports an issue that arose when atlas and cms first began to use preliminary numerical calculations of the dark matter relic density in these models. | recommendations of the lhc dark matter working group: comparing lhc searches for dark matter mediators in visible and invisible decay channels and calculations of the thermal relic density |
the radiative decay of neutral fermions has been studied for decades but cp violation induced within such a paradigm has evaded attention. cp violation in these processes can produce an asymmetry between circularly polarised directions of the radiated photons and produces an important source of net circular polarisation in particle and astroparticle physics observables. the results presented in this work outlines the general connection between cp violation and circular polarisation for both dirac and majorana fermions and can be used for any class of models that produce such radiative decays. the total cp violation is calculated based on a widely studied yukawa interaction considered in both active and sterile neutrino radiative decay scenarios as well as searches for dark matter via direct detection and collider signatures. finally, the phenomenological implications of the formalism on kev sterile neutrino decay, leptogenesis-induced right-handed neutrino radiative decay and icecube-driven heavy dark matter decay are discussed. | cp violation and circular polarisation in neutrino radiative decay |
the dark matter explanation of the 3.5 kev line is strongly disfavored by our work in dessert et al. (2020). boyarsky et al. (2004) questions that conclusion: modeling additional background lines is claimed to weaken the limit sufficiently to re-allow a dark matter interpretation. we respond as follows. (1) a more conservative limit is obtained by modeling additional lines; this point appeared in its entirety in our work in dessert et al. (2020), though we also showed that the inclusion of such lines is not necessary. (2) despite suggestions in boyarsky et al. (2004), even the more conservative limits strongly disfavor a decaying dark matter origin of the 3.5 kev line. | response to a comment on dessert et al. "the dark matter interpretation of the 3.5 kev line is inconsistent with blank-sky observations" |
the new minimal supersymmetric standard model (nmssm), a variant of the general next to minimal supersymmetric standard model (nmssm) without z 3 symmetry, features a naturally light singlino with a mass below 75 gev. in light of the new constraints from lhc run-1 on the higgs couplings, sparticles searches and flavour observables, we define the parameter space of the model which is compatible with both collider and dark matter (dm) properties. among the regions compatible with these constraints, implemented through nmssmtools, smodels and madanalysis5, only one with a singlino lightest supersymmetric particle (lsp) with a mass around 5 gev can explain all the dm abundance of the universe, while heavier mixed singlinos can only form one of the dm components. typical collider signatures for each region of the parameter space are investigated. in particular, the decay of the 125 gev higgs into light scalars and/or pseudoscalars and the decay of the heavy higgs into charginos and neutralinos, provide distinctive signatures of the model. moreover, the sfermion decays usually proceed through heavier neutralinos rather than directly into the lsp, as the couplings to the singlino are suppressed. we also show that direct detection searches are complementary to collider ones, and that a future ton-scale detector could completely probe the region of parameter space with a lsp mass around 65 gev. | status and prospects of the nmssm after lhc run-1 |
we present a feasibility study, to search for dark matter at the lhc, in events with one soft hadronically decaying tau lepton and missing transverse energy recoiling against a hard pt jet from initial state radiation. this methodology allows the search for supersymmetry in compressed mass spectra regions, where the mass difference between the lightest neutralino, χ∼10, and the stau (the tau superpartner), τ ∼, is small. several theoretical models predict a direct connection between thermal bino dark matter and staus within this scenario. we show that compressed regions, not excluded by atlas nor cms experiments, are opened up with the increase in experimental sensitivity reached with the proposed methodology. the requirement of a hard jet from initial state radiation combined with a soft tau lepton is effective in reducing standard model backgrounds, providing expected significances greater than 3 σ for χ∼1± masses up to 300 gev and τ ∼-χ∼10 mass gaps below 25 gev with only 30 fb-1 of 13 tev data from the lhc. | probing the stau-neutralino coannihilation region at the lhc with a soft tau lepton and a jet from initial state radiation |
we study the propagation of strongly interacting rydberg polaritons through an atomic medium in a one-dimensional optical lattice. we derive an effective single-band hubbard model to describe the dynamics of the dark-state polaritons under realistic assumptions. within this model, we analyze the driven-dissipative transport of polaritons through the system by considering a coherent drive on one side and by including the spontaneous emission of the metastable rydberg state. using a variational approach to solve the many-body problem, we find strong antibunching of the outgoing photons despite the losses from the rydberg state decay. | quantum many-body dynamics of driven-dissipative rydberg polaritons |
we argue that the standard model (sm) in the higgs phase does not suffer from a "hierarchy problem" and that similarly the "cosmological constant problem" resolves itself if we understand the sm as a low energy effective theory emerging from a cutoff-medium at the planck scale. we actually take serious veltman's "the infrared-ultraviolet connection" addressing the issue of quadratic divergences and the related huge radiative correction predicted by the sm in the relationship between the bare and the renormalized theory, usually called "the hierarchy problem" and claimed that this has to be cured. we discuss these issues under the condition of a stable higgs vacuum, which allows extending the sm up to the planck cutoff. the bare higgs boson mass then changes sign below the planck scale, such that the sm in the early universe is in the symmetric phase. the cutoff enhanced higgs mass term as well as the quartically enhanced cosmological constant term provide a large positive dark energy that triggers the inflation of the early universe. reheating follows via the decays of the four unstable heavy higgs particles, predominantly into top-antitop pairs, which at this stage are massless. preheating is suppressed in sm inflation since in the symmetric phase bosonic decay channels are absent at tree level. the coefficients of the shift between bare and renormalized higgs mass as well as of the shift between bare and renormalized vacuum energy density exhibit close-by zeros at about 7.7 × 10^{14} gev and 3.1 × 10^{15} gev, respectively. the zero of the higgs mass counter term triggers the electroweak phase transition, from the low energy higgs phase and to the symmetric phase above the transition point. since inflation tunes the total energy density to take the critical value of a flat universe and all contributing components are positive, it is obvious that the cosmological constant today is naturally a substantial fraction of the total critical density. thus taking cutoff enhanced corrections seriously the higgs system provides besides the masses of particles in the higgs phase also dark energy, inflation and reheating in the early universe. the main unsolved problem in our context remains the origin of dark matter. higgs inflation is possible and likely even unavoidable provided new physics does not disturb the known relevant sm properties substantially. the scenario highly favors to understand the sm and its main properties as a natural structure emerging at long distance. this in particular concerns the sm symmetry patterns and their consequences. | the hierarchy problem and the cosmological constant problem revisited |
we investigate the phenomenology of the light charged and neutral scalars in inert doublet model at future e + e - colliders with center of mass energies of 0.5 and 1 tev, and integrated luminosity of 500 fb-1. the analysis covers two production processes, e + e - → h + h - and e + e - → ah, and consists of signal selections, cross section determinations as well as dark matter mass measurements. several benchmark points are studied with focus on h ± → w ± h and a → zh decays. it is concluded that the signal will be well observable in different final states allowing for mass determination of all new scalars with statistical precision of the order of few hundred mev. | production of inert scalars at the high energy e + e - colliders |
tensions between cosmological parameters (in particular the local expansion rate h0 and the amplitude of matter clustering s8) inferred from low-redshift data and data from the cosmic microwave background (cmb) and large-scale structure experiments have inspired many extensions to the standard cosmological model, λ cdm . models which simultaneously lessen both tensions are of particular interest. we consider one scenario with the potential for such a resolution, in which some fraction of the dark matter has converted into dark radiation since the release of the cmb. such a scenario encompasses and generalizes the more standard "decaying dark matter" model, allowing additional flexibility in the rate and time at which the dark matter converts into dark radiation. in this paper, we constrain this scenario with a focus on exploring whether it can solve (or reduce) these tensions. we find that such a model is effectively ruled out by cmb data, in particular by the reduced peak-smearing due to cmb lensing on the power spectrum and the excess integrated sachs-wolfe signal caused by the additional dark energy density required to preserve flatness after dark matter conversion into dark radiation. thus, such a model does not have the power to reduce these tensions without further modifications. this conclusion extends and generalizes related conclusions derived for the standard decaying dark matter model. | converting dark matter to dark radiation does not solve cosmological tensions |
we show that the decay of the inflaton field may be incomplete, while nevertheless successfully reheating the universe and leaving a stable remnant that accounts for the present dark matter abundance. we note, in particular, that since the mass of the inflaton decay products is field dependent, one can construct models, endowed with an appropriate discrete symmetry, where inflaton decay is kinematically forbidden at late times and only occurs during the initial stages of field oscillations after inflation. we show that this is sufficient to ensure the transition to a radiation-dominated era and that inflaton particles typically thermalize in the process. they eventually decouple and freeze out, yielding a thermal dark matter relic. we discuss possible implementations of this generic mechanism within consistent cosmological and particle physics scenarios, for both single-field and hybrid inflation. | inflaton dark matter from incomplete decay |
we review results from qcd axion string and domain wall simulations and propagate the associated uncertainties, including qcd uncertainties, into the calculation of the axion relic density. we compare two different sets of studies and, using cosmological constraints, perform statistical inference on the axion mass window in the post-inflationary peccei-quinn symmetry breaking scenario. for dark matter axions in recent simulations inferring a moderately infrared-dominated spectrum, this leads to a median dark matter axion mass of 0.50 mev, while the 95% credible interval at highest posterior density is between 0.48 and 0.52 mev. for alternative simulations including in addition string-domain wall decays (but with different overall inference on the spectrum), these numbers are 0.22 mev and [0.16, 0.27] mev. relaxing the condition that axions are all of the dark matter, the axion mass window is completed by an upper bound of around 80 mev, which comes from dark radiation constraints. this confirms that the axion mass can be constrained rather precisely regarding statistical uncertainties and further calls for a more detailed analysis of the various sources of systematic uncertainties plaguing the simulations. | statistical uncertainties of the ndw = 1 qcd axion mass window from topological defects |
the cryogenic rare event search with superconducting thermometers (cresst) experiment aims at the direct detection of dark matter particles via their elastic scattering off nuclei in a scintillating cawo$$_4$$ 4 target crystal. the cawo$$_4$$ 4 crystal is operated together with a light detector at mk temperature and read out by a transition edge sensor. for many years, cawo$$_4$$ 4 crystals have successfully been produced in-house at technical university of munich (tum) with a focus on high radiopurity which is crucial to reduce background originating from radioactive contamination. in order to further improve the cawo$$_4$$ 4 crystals, an extensive chemical purification of the raw materials and the synthesised cawo$$_4$$ 4 powder has been performed. in addition, a temperature gradient simulation of the growth process and subsequently an optimisation of the growth furnace with the goal to reduce the intrinsic stress was carried out. we present results on the intrinsic stress in the cawo$$_4$$ 4 crystals and on the cawo$$_4$$ 4 powder radiopurity. a crystal grown from the purified material was installed in the current cresst set-up. the detector is equipped with an instrumented holder which is used to measure the alpha decay rate of the crystal. we present a preliminary analysis showing a significantly reduced intrinsic background from natural decay chains. | improving the quality of cawo4 target crystals for cresst |
the nature of neutrinos, whether dirac or majorana, is hitherto not known. assuming that the neutrinos are dirac, which needs b -l to be an exact symmetry, we make an attempt to explain the observed proportionality between the relic densities of dark matter (dm) and baryonic matter in the present universe i.e., ωdm≈5 ωb. we extend the standard model (sm) by introducing heavy scalar doublets xi,i =1 , 2 and η , two singlet scalars φ and φ' , a vectorlike dirac fermion χ representing the dm and three right-handed neutrinos νr i,i =1 , 2, 3. assuming b -l is an exact symmetry of the early universe, the c p -violating out-of-equilibrium decay of heavy scalar doublets; xi,i =1 , 2 to the sm lepton doublet l and the right-handed neutrino νr, generate equal and opposite b -l asymmetry among left (νl) and right (νr)-handed neutrinos. we ensure that νl-νr equilibration does not occur until below the electroweak (ew) phase transition during which a part of the lepton asymmetry gets converted to dark matter asymmetry through a dimension eight operator, which conserves b -l symmetry and remains in thermal equilibrium above sphaleron decoupling temperature. a part of the remaining b -l asymmetry then gets converted to a net b asymmetry through ew-sphalerons which are active at a temperature above 100 gev. to alleviate the small-scale anomalies of λ cdm , we assume the dm (χ ) to be self-interacting via a light mediator φ , which not only depletes the symmetric component of the dm, but also paves a way to detect the dm at terrestrial laboratories through φ -h mixing, where h is the sm higgs doublet. | asymmetric self-interacting dark matter via dirac leptogenesis |
in this work we analyse the ultimate sensitivity of dark matter direct detection experiments to dark radiation in form of sm or semi-sterile neutrinos. this flux-component is assumed to be produced from dark matter decay. since dark radiation may mimic dark matter signals, we perform our analysis based on likelihood statistics that allows to test the distinguishability between signals and backgrounds. given the previous bounds from neutrino experiments, we find that xenon-based dark matter searches will not be able to probe new regions of the dark matter progenitor mass and lifetime parameter space when the decay products are sm neutrinos. in turn, if the decay instead happens to a fourth neutrino species with enhanced interactions to baryons, dr can either constitute the dominant background or a discoverable signal in direct detection experiments. in the former case, this lifts the "neutrino floor" for xenon-based experiments. | sensitivity of direct detection experiments to neutrino dark radiation from dark matter decay and a modified neutrino-floor |
we present a first calculation of the rate for plasmon production in semiconductors from nuclei recoiling against dark matter. the process is analogous to bremsstrahlung of transverse photon modes, but with a longitudinal plasmon mode emitted instead. for dark matter in the 10 mev—1 gev mass range, we find that the plasmon bremsstrahlung rate is 4-5 orders of magnitude smaller than that for elastic scattering, but 4-5 orders of magnitude larger than the transverse bremsstrahlung rate. because the plasmon can decay into electronic excitations and has characteristic energy given by the plasma frequency ωp, with ωp≈16 ev in si crystals, plasmon production provides a new signature and method to detect nuclear recoils from sub-gev dark matter. | plasmon production from dark matter scattering |
one of the most significant and practical figures of merit in axion haloscope searches is the scanning rate, because of the unknown axion mass. under the best experimental parameters, the only way to improve the figure of merit is to increase the experimentally designed signal to noise ratio in the axion haloscope search analysis procedure. in this paper, we report an improved axion haloscope search analysis using the data taken by the capp-8tb haloscope. by correcting for the background biased by the background parametrizations in the presence of axion signals, we realized a signal to noise ratio efficiency of about 100%. given the axion haloscope search analyses to date, the scanning rate can be improved by 21%, with about a 10% improvement in the signal to noise ratio. this improvement is another low cost innovation in axion haloscope searches, where all the experimental parameters are currently at their best. | improved axion haloscope search analysis |
global fit studies performed in the pmssm and the photon excess signal originating from the galactic center seem to suggest compressed electroweak supersymmetric spectra with a ∼100 gev bino-like dark matter particle. we find that these scenarios are not probed by traditional electroweak supersymmetry searches at the lhc. we propose to extend the atlas and cms electroweak supersymmetry searches with an improved strategy for bino-like dark matter, focusing on chargino plus next-to-lightest neutralino production, with a subsequent decay into a tri-lepton final state. we explore the sensitivity for pmssm scenarios with δ m = m nlsp - m lsp ∼ (5 - 50) gev in the √{s} = 14 tev run of the lhc. counterintuitively, we find that the requirement of low missing transverse energy increases the sensitivity compared to the current atlas and cms searches. with 300 fb-1 of data we expect the lhc experiments to be able to discover these supersymmetric spectra with mass gaps down to δ m ∼ 9 gev for dm masses between 40 and 140 gev. we stress the importance of a dedicated search strategy that targets precisely these favored pmssm spectra. | the case for 100 gev bino dark matter: a dedicated lhc tri-lepton search |
we investigate predictions of the trilinear higgs self-coupling with radiative corrections in the context of the inert doublet model. the triple higgs vertex is computed at the one-loop level based on the on-shell renormalization scheme. we calculate its possible deviation from the predictions within the standard model, taking into account all relevant theoretical and experimental constraints, including dark matter searches and the latest bounds on the branching fraction of the higgs boson decaying to invisible particles. by scanning the model's parameter space, we find that the deviation in the triple higgs boson self-coupling from standard model expectations can be substantial, exceeding 100% in certain regions of the parameter space. | revisiting one-loop corrections to the trilinear higgs boson self-coupling in the inert doublet model |
searches for axionlike particles (alps) are motivated by the strong c p problem in particle physics and by unexplained dark matter in astrophysics. in this paper, we discuss novel alp searches using monoenergetic nuclear deexcitation photons from a beam dump, using the isotope decay-at-rest (isodar) experiment as an example. we show that isodar can set limits that close a gap in traditional qcd axion searches using the alp-photon coupling, as well as provide sensitivity to large regions of new parameter space in models where alps couple to nucleons and electrons. we also show how isotope decay-at-rest experiments may be designed to improve potential alp production and optimize detection sensitivity. | axionlike particle production at beam dump experiments with distinct nuclear excitation lines |
the scintillation characteristics of a thallium-doped sodium iodide (nai(tl)) crystal with dimensions of 0.6 cm× 0.6 cm× 2 cm were studied by attaching a silicon photomultiplier (sipm) directly to the crystal over a temperature range of 93-300 k. the scintillation light output and decay time were measured by irradiating 59.54 kev γ-rays with a 241am source. we observed an approximately 20% increase in the light yield at 230 k compared with that at room temperature. under these conditions, nai(tl) crystals with sipm readout can be suitable for future dark matter search detectors. | scintillation characteristics of a nai(tl) crystal at low-temperature with silicon photomultiplier |
the singlet majoron model of seesaw neutrino mass is appended by one dark majorana fermion singlet χ with l =2 and one dark complex scalar singlet ζ with l =1 . this simple setup allows χ to obtain a small radiative mass anchored by the same heavy right-handed neutrinos, whereas the one-loop decay of the standard model higgs boson to χ χ +χ ¯χ ¯ provides the freeze-in mechanism for χ to be the light dark matter of the universe. | radiative seesaw dark matter |
the rest-for-physics (rare event searches toolkit for physics) framework is a root-based solution providing the means to process and analyze experimental or monte carlo event data. special care has been taken to the traceability of the code and the validation of the results produced within the framework, together with the connectivity between code and stored data, registered through specific version metadata members. the framework development was originally motivated to cover the needs of rare event searches experiments (experiments looking for phenomena having extremely low occurrence probability, like dark matter or neutrino interactions or rare nuclear decays). the framework components naturally implement tools to address the challenges in these kinds of experiments. the integration of a detector physics response, the implementation of signal processing routines, or topological algorithms for physical event identification are some examples. despite this specialization, the framework was conceived thinking in scalability. other event-oriented applications could benefit from the data processing routines and/or metadata description implemented in rest, being the generic framework tools completely decoupled from dedicated libraries. rest-for-physics is a consolidated piece of software already serving the needs of different physics experiments - using gaseous time projection chambers (tpcs) as detection technology - for detector data analysis and characterization, as well as generic r&d. even though rest has been exploited mainly with gaseous tpcs, the code could be easily applied or adapted to other detector technologies. we present in this work an overview of rest-for-physics, providing a broad perspective to the infrastructure and organization of the project as a whole. the framework and its different components will be described in the text. | rest-for-physics, a root-based framework for event oriented data analysis and combined monte carlo response |
we study dark matter freeze-in scenarios where the mass of the mediator particle that couples dark matter to the standard model is larger than the reheat temperature, trh, in the early universe. in such setups, the standard approach is to work with an effective field theory (eft) where the mediator is integrated out. we examine the validity of this approach in various generic s- and t-channel mediator frameworks. we find that the eft approach breaks down when the mediator mass is between one to two orders of magnitude larger than trh due to various effects such as s-channel resonance, a small thermally-suppressed abundance of the mediator, or decays of standard model particles through loops induced by the mediator. this highlights the necessity of including these contributions in such dark matter freeze-in studies. we also discuss the collider phenomenology of the heavy mediators, which is qualitatively different from standard freeze-in scenarios. we highlight that, due to the low trh, the standard model-dark matter coupling in these scenarios can be relatively larger than in standard freeze-in scenarios, improving the testability prospects of these setups. | dark matter freeze-in with a heavy mediator: beyond the eft approach |
if the dark matter in the universe is made of $\mu$ev axion-like particles (alps), then a rich phenomenology can emerge in connection to their stimulated decay into two photons. we discuss the alp stimulated decay induced by astrophysical beams of galactic radio sources. three signatures, made by two echoes and one collinear emission, are associated with the decay, and can be simultaneously detected, offering a unique opportunity for a clear alp identification. we derive the formalism associated with such signatures starting from first principles, and providing the relevant equations to be applied to study the alp phenomenology. we then focus on the case of galactic pulsars as stimulating sources and derive forecasts for future observations. | anatomy of astrophysical echoes from axion dark matter |
several extensions of the standard model predict the production of dark matter particles at the lhc. an uncharted signature of dark matter particles produced in association with v v =w±w∓ or z z pairs from a decay of a dark higgs boson s is searched for using 139 fb-1 of p p collisions recorded by the atlas detector at a center-of-mass energy of 13 tev. the s →v (q q ¯)v (q q ¯) decays are reconstructed with a novel technique aimed at resolving the dense topology from boosted v v pairs using jets in the calorimeter and tracking information. dark higgs scenarios with ms>160 gev are excluded. | search for dark matter produced in association with a dark higgs boson decaying into w±w∓ or z z in fully hadronic final states from √{s }=13 tev p p collisions recorded with the atlas detector |
initial conditions for (newtonian) cosmological n-body simulations are usually set by re-scaling the present-day power spectrum obtained from linear (relativistic) boltzmann codes to the desired initial redshift of the simulation. this back-scaling method can account for the effect of inhomogeneous residual thermal radiation at early times, which is absent in the newtonian simulations. we analyse this procedure from a fully relativistic perspective, employing the recently-proposed newtonian motion gauge framework. we find that n-body simulations for λcdm cosmology starting from back-scaled initial conditions can be self-consistently embedded in a relativistic space-time with first-order metric potentials calculated using a linear boltzmann code. this space-time coincides with a simple ``n-body gauge'' for z < 50 for all observable modes. care must be taken, however, when simulating non-standard cosmologies. as an example, we analyse the back-scaling method in a cosmology with decaying dark matter, and show that metric perturbations become large at early times in the back-scaling approach, indicating a breakdown of the perturbative description. we suggest a suitable ``forwards approach" for such cases. | relativistic initial conditions for n-body simulations |
the extension of the standard model by a real gauge singlet scalar is the simplest but the most studied model with sometimes controversial ideas on the ability of the model to address the dark matter and the electroweak phase transition issues simultaneously. for this model, we obtain analytically slightly different conditions for strongly first-order electroweak phase transition and apply that in computation of the dark matter relic density where the real scalar plays the role of the dark matter particle. we show that the scalar in this model before imposing the invisible higgs decay constraint, can be responsible for all or part of the dark matter abundance, while at the same time gives rise to a strongly first-order electroweak phase transition required for the baryogenesis. when the constraints from the direct detection experiments such as xenon100 or lux/xenon1t are considered, the model is excluded completely. | strongly first-order phase transition in real singlet scalar dark matter model |
we propose a new scenario of early dark energy (ede) with a dark higgs field trapped at the origin. to keep this dark higgs trapped until around the matter-radiation equality, we use dark photons produced nonthermally by coherent oscillations of axions, which have a much stronger trapping effect than thermal mass. when the trapping ends, the dark higgs quickly decays into dark photons, which are then redshifted as radiation. in fact, dark photons are self-interacting dark radiation, and the dark higgs field can also be in thermal equilibrium if its self-coupling is small enough. in some cases, these particles can act as the wess-zumino dark radiation. the dark higgs ede scenario works well for an ordinary mexican-hat potential, and the dark higgs naturally sits at the origin from the beginning, since it is the symmetry-enhanced point. thus, unlike the axion ede, there is no need for elaborate potentials or fine-tuning with respect to the initial condition. interestingly, the axion not only produces dark photons, but also explains dark matter. we find the viable parameter region of the axion decay constant and the axion mass where dark matter and the h0 tension can be simultaneously explained. we also discuss the detectability of the axion in the presence of axion-photon coupling, and show that the axion can be the qcd axion. | early dark energy by a dark higgs field and axion-induced nonthermal trapping |
the observation of light super-partners from a supersymmetric extension to the standard model is an intensely sought-after experimental outcome, providing an explanation for the stabilization of the electroweak scale and indicating the existence of new particles which could be consistent with dark matter phenomenology. for compressed scenarios, where sparticle spectra mass-splittings are small and decay products carry low momenta, dedicated techniques are required in all searches for supersymmetry. in this paper we suggest an approach for these analyses based on the concept of recursive jigsaw reconstruction, decomposing each event into a basis of complementary observables, for cases where strong initial state radiation has sufficient transverse momentum to elicit the recoil of any final state sparticles. we introduce a collection of kinematic observables which can be used to probe compressed scenarios, in particular exploiting the correlation between missing momentum and that of radiative jets. as an example, we study squark and gluino production, focusing on mass-splittings between parent super-particles and their lightest decay products between 25 and 200 gev, in hadronic final states where there is an ambiguity in the provenance of reconstructed jets. | sparticles in motion - getting to the line in compressed scenarios with the recursive jigsaw reconstruction |
the padme experiment, at the laboratori nazionali di frascati (lnf), in italy, will search for invisible decays of the hypothetical dark photon via the process e+e- → γa‧, where the a‧ escapes detection. the dark photon mass range sensitivity in a first phase will be 1 to 24 mev. we report here on performance measurements and simulation studies of a prototype of the small-angle calorimeter, a component of padme's detector dedicated to rejecting 2- and 3-gamma backgrounds. the crucial requirement is a timing resolution of less than 200 ps, which is satisfied by the choice of pbf2 crystals and the newly released hamamatsu r13478uv photomultiplier tubes (pmts). we find a timing resolution of 81 ps (with double-peak separation resolution of 1.8 ns) and a single-crystal energy resolution of 10% at 550 mev with light yield of 2.05 photo-electrons per mev, using 100 to 400 mev electrons at the beam test facility of lnf. we also propose the investigation of a two-pmt solution coupled to a single pbf2 crystal for higher-energy applications, which has potentially attractive features. | characterization and performance of padme's cherenkov-based small-angle calorimeter |
we propose a possible string embedding of affleck-dine baryogenesis in type iib sequestered models where the late-time decay of the lightest modulus reheats the universe to relatively low temperatures. we show that if inflation is driven by a blow-up kähler modulus, the affleck-dine field can become tachyonic during inflation if the kähler metric for matter fields has an appropriate inflaton-dependent contribution. we find that the affleck-dine mechanism can generate the observed baryon asymmetry for natural values of the underlying parameters which lead also to successful inflation and low-energy gaugino masses in a split supersymmetry scenario. the reheating temperature from the lightest modulus decay is high enough to allow thermal higgsino-like dark matter. | affleck-dine baryogenesis in type iib string models |
we propose a new nonthermal mechanism of dark matter production based on vacuum misalignment. a global x -charge asymmetry is generated at high temperatures, under which both the will-be higgs boson and the dark matter are charged. at lower energies, the vacuum changes alignment and breaks the u (1 )x, leading to the emergence of the higgs bosonand of a fraction of charge asymmetry stored in the stable dark matter relic. this mechanism can be present in a wide variety of models based on vacuum misalignment, and we demonstrate it in a composite higgs template model, where all the necessary ingredients are naturally present. a light pseudo-scalar η is always predicted, with interesting implications for cosmology, future supernova observations and exotic z →γ η decays. | higgs boson emerging from the dark |
i review a string-inspired cosmological model with gravitational anomalies in its early epochs, which is based on fields from the (bosonic) massless gravitational multiplet of strings, in particular gravitons and kalb ramond (kr), string-model independent, axions (the dilaton is assumed constant). i show how condensation of primordial gravitational waves, which are generared at the very early eras immediately after the big bang, can lead to inflation of the so called running vacuum model (rvm) type, without external inflatons. the role of the slow-roll field is played by the kr axion, but it does not drive inflation. the non-linearities in the anomaly terms do. chiral fermionic matter excitations appear at the end of this rvm inflation, as a result of the decay of the rvm vacuum, and are held responsible for the cancellation of the primordial gravitational anomalies. chiral anomalies, however, survive in the post-inflationary epochs, and can lead to the generation of a non perturbative mass for the kr axion, which could thus play the role of dark matter in this universe. as a result of the condensed gravitational anomaly, there is a lorentz-invariance violating kr axion background, which remains undiluted during the rvm inflation, and can lead to baryogenesis through leptogenesis in the radiation era, in models with sterile right-handed neutrinos. i also discuss the phenomenology of the model in the modern era, paying particular attention to linking it with a version of rvm, called type ii rvm, which arguably can alleviate observed tensions in the current-epoch cosmological data. | gravitational anomalies, axions and a string-inspired running vacuum model in cosmology |
since its discovery, the environmental instability of exfoliated black phosphorus (2d bp) has emerged as a challenge that hampers its wide application in chemistry, physics, and materials science. many studies have been carried out to overcome this drawback. here we show a relevant enhancement of ambient stability in few-layer bp decorated with nickel nanoparticles as compared to pristine bp. in detail, the behavior of the ni-functionalized material exposed to ambient conditions in the dark is accurately studied by transmission electron microscopy (tem), raman spectroscopy, and high resolution x-ray photoemission and absorption spectroscopy. these techniques provide a morphological and quantitative insight of the oxidation process taking place at the surface of the bp flakes. in the presence of ni nanoparticles (nps), the decay time of 2d bp to phosphorus oxides is more than three time slower compared to pristine bp, demonstrating an improved structural stability within 20 months of observation. | enhanced ambient stability of exfoliated black phosphorus by passivation with nickel nanoparticles |
the 11be neutron halo nucleus appears to decay into 10be with a rate that exceeds expectations. neutron disappearance into dark matter, beta decay of a halo neutron, or beta-delayed proton decay have been offered as explanations. in this work we study the latter option; we carry out shell model calculations and sequential decay analysis examining the beta-delayed proton decay going through a resonance in 11b. the narrow energy window, lack of states with sufficient spectroscopic strength, overwhelming alpha decay branch, all make reconciling the observed rate with beta-delayed proton decay difficult. | assessment of the beta-delayed proton decay rate of 11be |
despite evidence for the existence of dark matter (dm) from very high and low redshifts, a moderate amount of dm particle decay remains a valid possibility. this includes both models with very long-lived yet unstable particles or mixed scenarios where only a small fraction of dark matter is allowed to decay. in this paper, we investigate how dm particles decaying into radiation affect non-linear structure formation. we look at the power spectrum and its redshift evolution, varying both the decay lifetime (τ) and the fraction of decaying-to-total dark matter (f), and we propose a fitting function that reaches sub-percent precision below k ~ 10 h/mpc. based on this fit, we perform a forecast analysis for a euclid-like weak lensing (wl) survey, including both massive neutrino and baryonic feedback parameters. we find that with wl observations alone, it is possible to rule out decay lifetimes smaller than τ = 75 gyr (at 95 percent cl) for the case that all dm is unstable. this constraint improves to τ = 182 gyr if the wl data is combined with cmb priors from the planck satellite and to τ = 275 gyr if we further assume baryonic feedback to be fully constrained by upcoming sunyaev-zeldovich or x-ray data. the latter shows a factor of 3.2 improvement compared to constraints from cmb data alone. regarding the scenario of a strongly decaying sub-component of dark matter with τ ~ 30 gyr or lower, it will be possible to rule out a decaying-to-total fraction of f > 0.49, f > 0.21, and f > 0.13 (at the 95 percent cl) for the same three scenarios. we conclude that the upcoming stage-iv wl surveys will allow us to significantly improve current constraints on the stability of the dark matter sector. | decaying dark matter: simulations and weak-lensing forecast |
by quenching the interatomic interactions, we investigate the nonequilibrium dynamics of two-dimensional bose-einstein condensates in boxlike traps with power-law potential boundaries. we show that ring dark solitons can be excited during the quench dynamics for both concave and convex potentials. the quench's modulation strength and the steepness of the boundary are two major factors influencing the system's evolution. in terms of the number of ring dark solitons excited in the condensate, five dynamic regimes have been identified. the condensate undergoes damped radius oscillation in the absence of ring dark soliton excitations. when it comes to the appearance of ring dark solitons, their decay produces interesting structures. the excitation patterns for the concave potential show a nested structure of vortex-antivortex pairs. the dynamic excitation patterns for the convex potential, on the other hand, show richer structures with multiple transport behaviors. | quench dynamics of bose-einstein condensates in boxlike traps |
several extensions of the standard model predict the production of dark matter particles at the lhc. a search for dark matter particles produced in association with a dark higgs boson decaying into $w^{+}w^{-}$ in the $\ell^\pm\nu q \bar q'$ final states with $\ell=e,\mu$ is presented. this analysis uses 139 fb$^{-1}$ of $pp$ collisions recorded by the atlas detector at a centre-of-mass energy of 13 tev. the $w^\pm \to q\bar q'$ decays are reconstructed from pairs of calorimeter-measured jets or from track-assisted reclustered jets, a technique aimed at resolving the dense topology from a pair of boosted quarks using jets in the calorimeter and tracking information. the observed data are found to agree with standard model predictions. scenarios with dark higgs boson masses ranging between 140 and 390 gev are excluded. | search for dark matter produced in association with a dark higgs boson decaying into $w^{+}w^{-}$ in the one-lepton final state at $\\sqrt{s}$=13 tev using 139 fb$^{-1}$ of $pp$ collisions recorded with the atlas detector |
recent proposals have suggested that a previously unknown decay mode of the neutron into a dark matter particle could solve the long lasting measurement problem of the neutron decay width. we show that, if the dark particle in neutron decay is the major component of the dark matter in the universe, this proposal is in disagreement with modern astrophysical data concerning neutron star masses. | neutron to dark matter decay in neutron stars |
it was recently proposed that the disagreement in the experimental measurements of the lifetime of the neutron might be eradicated if the neutron decays to particles responsible for the dark matter in the universe. in this paper we construct a prototype self-interacting dark matter model which, apart from reproducing the correct relic abundance, resolves all small-scale problems of the λcdm paradigm. the theory is compatible with the present cosmological observations and astrophysical bounds. | small-scale structure from neutron dark decay |
a search is presented for dark matter in proton-proton collisions at a center-of-mass energy of $\sqrt{s} =$ 13 tev using events with at least one high transverse momentum ($p_\mathrm{t}$) muon, at least one high-$p_\mathrm{t}$ jet, and large missing transverse momentum. the data were collected with the cms detector at the cern lhc in 2016 and 2017, and correspond to an integrated luminosity of 77.4 fb$^{-1}$. in the examined scenario, a pair of scalar leptoquarks is assumed to be produced. one leptoquark decays to a muon and a jet while the other decays to dark matter and low-$p_\mathrm{t}$ standard model particles. the signature for signal events would be significant missing transverse momentum from the dark matter in conjunction with a peak at the leptoquark mass in the invariant mass distribution of the highest $p_\mathrm{t}$ muon and jet. the data are observed to be consistent with the background predicted by the standard model. for the first benchmark scenario considered, dark matter masses up to 500 gev are excluded for leptoquark masses $m_\mathrm{lq}$ $\approx$ 1400 gev, and up to 300 gev for $m_\mathrm{lq}$ $\approx$ 1500 gev. for the second benchmark scenario, dark matter masses up to 600 gev are excluded for $m_\mathrm{lq}$ $\approx$ 1400 gev. | search for dark matter in events with a leptoquark and missing transverse momentum in proton-proton collisions at 13 tev |
a number of proposals have been put forward for detecting axion dark matter (dm) with grand unification scale decay constants that rely on the conversion of coherent dm axions to oscillating magnetic fields in the presence of static, laboratory magnetic fields. crucially, such experiments—including abracadabra—have to date worked in the limit that the axion compton wavelength is larger than the size of the experiment, which allows one to take a magnetoquasistatic (mqs) approach to characterize the detector apparatus and model the axion signal. we use finite element methods to solve the coupled axion-electromagnetism equations of motion without assuming the mqs approximation. we show that the mqs approximation becomes a poor approximation at frequencies 2 orders of magnitude lower than the naive mqs limit frequency commonly defined by the inverse diameter of a lumped-element detector. radiation losses diminish the quality factor of an otherwise high-q resonant readout circuit, though this may be mitigated through shielding and minimizing lossy materials. additionally, self-resonances associated with the detector geometry change the reactive properties of the pickup system, leading to two generic features beyond mqs: there are frequencies that require an inductive rather than capacitive tuning to maintain resonance, and the detector itself becomes a multipole resonator at high frequencies. accounting for these features, competitive sensitivity to the axion-photon coupling may be extended well beyond the naive mqs limit. | lumped-element axion dark matter detection beyond the magnetoquasistatic limit |
a search for dark matter particles is performed by looking for events with large transverse momentum imbalance and a recoiling higgs boson decaying to either a pair of photons or a pair of τ leptons. the search is based on proton-proton collision data at a center-of-mass energy of 13 tev collected at the cern lhc in 2016 and corresponding to an integrated luminosity of 35.9 fb-1. no significant excess over the expected standard model background is observed. upper limits at 95% confidence level are presented for the product of the production cross section and branching fraction in the context of two benchmark simplified models. for the z'-two-higgs-doublet model (where z' is a new massive boson mediator) with an intermediate heavy pseudoscalar particle of mass m a = 300 gev and m dm = 100 gev, the z' masses from 550 gev to 1265 gev are excluded. for a baryonic z' model, with m dm = 1 gev, z' masses up to 615 gev are excluded. results are also presented for the spin-independent cross section for the dark matter-nucleon interaction as a function of the mass of the dark matter particle. this is the first search for dark matter particles produced in association with a higgs boson decaying to two τ leptons. [figure not available: see fulltext.] | search for dark matter produced in association with a higgs boson decaying to γγ or τ + τ - at √{s}=13 tev |
we have searched for axion-like resonance states by colliding optical photons in a focused laser field (creation beam) by adding another laser field (inducing beam) for stimulation of the resonance decays, where frequency-converted signal photons can be created as a result of stimulated photon-photon scattering via exchanges of axion-like resonances. a quasi-parallel collision system (qps) in such a focused field allows access to the sub-ev mass range of resonance particles. in past searches in qps, for simplicity, we interpreted the scattering rate based on an analytically calculable symmetric collision geometry in both incident angles and incident energies by partially implementing the asymmetric nature to meet the actual experimental conditions. in this paper, we present new search results based on a complete parameterization including fully asymmetric collisional geometries. in particular, we combined a linearly polarized creation laser and a circularly polarized inducing laser to match the new parameterization. a 0.10 mj/31 fs ti:sapphire laser pulse and a 0.20 mj/9 ns nd:yag laser pulse were spatiotemporally synchronized by sharing a common optical axis and focused into the vacuum system. under a condition in which atomic background processes were completely negligible, no significant scattering signal was observed at the vacuum pressure of 2.6 × 10−5 pa, thereby providing upper bounds on the coupling-mass relation by assuming exchanges of scalar and pseudoscalar fields at a 95% confidence level in the sub-ev mass range. | search for sub-ev axion-like resonance states via stimulated quasi-parallel laser collisions with the parameterization including fully asymmetric collisional geometry |
an axion-like particle (alp) with mass mϕ ∼ 10-15 ev oscillates with frequency ∼1 hz. this mass scale lies in an open window of astrophysical constraints, and appears naturally as a consequence of grand unification (gut) in string/m-theory. however, with a gut-scale decay constant such an alp overcloses the universe, and cannot solve the strong cp problem. in this paper, we present a two axion model in which the 1 hz alp constitutes the entirety of the dark matter (dm) while the qcd axion solves the strong cp problem but contributes negligibly to the dm relic density. the mechanism to achieve the correct relic densities relies on low-scale inflation (mϕ ≲ hinf ≲ 1 mev), and we present explicit realisations of such a model. the scale in the axion potential leading to the 1 hz axion generates a value for the strong cp phase which oscillates around θ¯qcd∼10-12, within reach of the proton storage ring electric dipole moment experiment. the 1 hz axion is also in reach of near future laboratory and astrophysical searches. | opening the 1 hz axion window |
in this master's thesis we study the production of axion dark matter through the so-called misalignment mechanism by considering that during that time, the universe was dominated by a new kind of fluid, different than radiation. we perform a very detailed analysis of the oscillation temperature and the relic density today, both analytically and numerically. our findings show that on the one hand, the oscillation temperature is strongly influenced by the non-standard cosmology, affecting the relic density, and on the other hand, the energy density of the axion gets diluted, because the new fluid eventually decays, injecting entropy into the thermal bath. we find the predicted parameter space of axion dark matter for different non-standard cosmologies and we show its impact on the coupling of axions to two photons. | relic density of axion dark matter in standard and non-standard cosmological scenarios |
we show that string moduli have axionphilic nature owing to the model-insensitive derivative interactions arising from the kähler potential. the decay of a modulus into stringy axions occurs without suppression by the mass of final states. interestingly, it turns out to hold in general not only for the scalar partner of the stringy axion but also for any other moduli. the decay into (pseudo)-nambu-goldstone bosons (ngbs) also avoids such mass suppression if the modulus is lighter than or similar in mass to the scalar partner of the ngb. such axionphilic nature makes string moduli a natural source of an observable amount of dark radiation in string compactifications involving ultralight stringy axions, and possibly in extensions of the standard model that include a cosmologically stable ngb such as the qcd axion. in the latter case, the fermionic superpartner of the ngb can also contribute to the dark matter as a feebly interacting massive particle. | axionphilic cosmological moduli |
we propose a new alternative to the weakly interacting massive particle paradigm for dark matter. rather than being determined by thermal freeze-out, the dark matter abundance in this scenario is set by dark matter decay, which is allowed for a limited amount of time just before the electroweak phase transition. more specifically, we consider fermionic singlet dark matter particles coupled weakly to a scalar mediator s3 and to auxiliary dark sector fields, charged under the standard model gauge groups. dark matter freezes out while still relativistic, so its abundance is initially very large. as the universe cools down, the scalar mediator develops a vacuum expectation value (vev), which breaks the symmetry that stabilizes dark matter. this allows dark matter to mix with charged fermions and decay. during this epoch, the dark matter abundance is reduced to give the value observed today. later, the sm higgs field also develops a vev, which feeds back into the s3 potential and restores the dark sector symmetry. in a concrete model we show that this "vev flip-flop" scenario is phenomenologically successful in the most interesting regions of its parameter space. we also comment on detection prospects at the lhc and elsewhere. | dark matter decay between phase transitions at the weak scale |
a new mechanism for producing axion dark matter is proposed. by invoking low-scale inflation and a kinetic mixing between the axion and the inflaton, it is shown that the axion is driven to a field point slightly displaced from the potential minimum, which can give rise to the observed dark matter abundance. in this framework, different combinations of the axion and inflaton fields play various cosmological roles, including generating the cosmological perturbations, reheating the universe, and serving as dark matter. the kinetic mixing also relates the dark matter lifetime with the reheating temperature. the mechanism tames axions that would otherwise overdominate the universe, and thus opens up new windows in the axion parameter space, including decay constants at the gut scale and higher. | inflaxion dark matter |
in order to address the baryon asymmetry in the universe one needs to understand the origin of baryon and lepton number violation. in this article, we discuss the mechanism of baryogenesis via leptogenesis to explain the matter-antimatter asymmetry in theories with spontaneous breaking of baryon and lepton number. in this context, a lepton asymmetry is generated through the out-of-equilibrium decays of right-handed neutrinos at the high-scale, while local baryon number must be broken below the multi-tev scale to satisfy the cosmological bounds on the dark matter relic density. we demonstrate how the lepton asymmetry generated via leptogenesis can be converted in two different ways: (a) in the theory predicting majorana dark matter the lepton asymmetry is converted into a baryon asymmetry, and (b) in the theory with dirac dark matter the decays of right-handed neutrinos can generate lepton and dark matter asymmetries that are then partially converted into a baryon asymmetry. consequently, we show how to explain the matter-antimatter asymmetry, the dark matter relic density and neutrino masses in theories for local baryon and lepton number. | baryogenesis via leptogenesis: spontaneous b and l violation |
we present measurements of bulk radiocontaminants in the high-resistivity silicon ccds from the damic experiment at snolab. we utilize the exquisite spatial resolution of ccds to discriminate between α and β decays, and to search with high efficiency for the spatially-correlated decays of various radioisotope sequences. using spatially-correlated β decays, we measure a bulk radioactive contamination of 32si in the ccds of 140 ± 30 μbq/kg, and place an upper limit on bulk 210pb of < 160 μbq/kg. using similar analyses of spatially-correlated α and β decays, we set upper limits of < 11 μbq/kg (0.9 ppt) on 238u and < 7.3 μbq/kg (1.8 ppt) on 232th in the bulk silicon. the ability of damic ccds to identify and reject spatially-coincident backgrounds, particularly from 32si, has significant implications for the next generation of silicon-based dark matter experiments, where β's from 32si decay will likely be a dominant background. | measurement of the bulk radioactive contamination of detector-grade silicon with damic at snolab |
higgs signatures from the cascade decays of light top squarks are an interesting possibility in the next-to-minimal supersymmetric standard model (nmssm). we investigate the potential reach of the light top-squark mass at the 13 tev run of the lhc by means of five nmssm benchmark points where this signature is dominant. these benchmark points are compatible with current higgs coupling measurements, lhc constraints, dark matter relic density and direct-detection constraints. we consider single and dilepton search strategies, as well as the jet-substructure technique to reconstruct the higgs bosons. we find that one can probe top-squark masses up to 1.2 tev with 300 fb-1 luminosity via the dilepton channel, while with the jet-substructure method, top-squark masses up to 1 tev can be probed with 300 fb-1 luminosity. we also investigate the possibility of the appearance of multiple higgs peaks over the background in the fat-jet mass distribution, and conclude that such a possibility is viable only at the high-luminosity run of the 13 tev lhc. | probing the nmssm via higgs boson signatures from stop cascade decays at the lhc |
we reconsider the minimal su(5) grand unified theory (gut) in the context of no-scale supergravity inspired by string compactification scenarios, assuming that the soft supersymmetry-breaking parameters satisfy universality conditions at some input scale m_in above the gut scale m_{gut}. when setting up such a no-scale super-gut model, special attention must be paid to avoiding the scylla of rapid proton decay and the charybdis of an excessive density of cold dark matter, while also having an acceptable mass for the higgs boson. we do not find consistent solutions if none of the matter and higgs fields are assigned to twisted chiral supermultiplets, even in the presence of giudice-masiero terms. however, consistent solutions may be found if at least one fiveplet of gut higgs fields is assigned to a twisted chiral supermultiplet, with a suitable choice of modular weights. spin-independent dark matter scattering may be detectable in some of these consistent solutions. | no-scale su(5) super-guts |
it has recently been pointed out that the underlying symmetry of dark matter may well be $u(1)_\chi$ (coming from $so(10) \to su(5) \times u(1)_\chi$) with the dark parity of any given particle determined by $(-1)^{q_\chi+2j}$, where $q_\chi$ is its $u(1)_\chi$ charge and $j$ its spin angular momentum. armed with this new insight, previous simple models of dark matter are reinterpreted, and a novel idea is proposed that light seesaw dark matter exists in analogy to light neutrinos and is produced by the rare decay of the standard-model higgs boson. | u(1)_{\\chi}, seesaw dark matter, and higgs decay |
we present a minimal framework of $u(1)_{b-l}$ gauge extension of the standard model explaining dark matter abundance and matter-antimatter asymmetry simultaneously through an attractive mechanism of tev scale wimpy leptogenesis, testable at the current and next generation of colliders. this framework can also explain small neutrino masses via a radiative mechanism. one of the key predictions of this model is an enhanced rate for lepton flavor violating decay $\mu \rightarrow e \gamma$ within the sensitivity reach of next generation experiments. | a minimal model of tev scale wimpy leptogenesis |
we propose a new mechanism where asymmetric dark matter (adm) and the baryon asymmetry are both generated in the same decay chain of a metastable weakly interacting massive particle (wimp) after its thermal freezeout. dark matter and baryons are connected by a generalized baryon number that is conserved, while the dm asymmetry and baryon asymmetry compensate each other. this unified framework addresses the dm-baryon coincidence while inheriting the merit of the conventional wimp miracle in predicting relic abundances of matter. examples of renormalizable models realizing this scenario are presented. these models generically predict adm with sub-gev to gev-scale mass that interacts with standard model quarks or leptons, thus rendering potential signatures at direct detection experiments sensitive to low mass dm. other interesting phenomenological predictions are also discussed, including: lhc signatures of new intermediate particles with color or electroweak charge and dm induced nucleon decay; the long-lived wimp may be within reach of future high energy collider experiments. | wimp cogenesis for asymmetric dark matter and the baryon asymmetry |
suppose that the early universe starts with a cosmological $\lambda$-term originating from quantum spacetime at the planck scale. dark energy drives inflation and reheating by reducing its value for massive particle-antiparticle pairs production and oscillation, resulting in a holographic and massive pair plasma state. the back-and-forth reaction of dark energy and massive pairs slows inflation to its end and starts reheating by rapidly producing stable and unstable pairs. we introduce the boltzmann-type rate equation describing the back-and-forth reaction. it forms a close set with friedman equations and reheating equations for unstable pairs decay to relativistic particles. the numerical solutions show preheating, massive pairs dominated and genuine reheating episodes. we obtain the reheating temperature and entropy in terms of the tensor-to-scalar ratio $0 < r < 0.047$ consistently with observations. stable massive pairs represent cold dark matter particles and weakly interact with dark energy. the resultant cold dark matter abundance $\omega_c\sim 10^{-1}$ is about a constant in time. | massive particle pair production and oscillation in friedman universe: reheating energy and entropy, and cold dark matter |
we revisit a cosmological constraint on dark matter decaying into dark radiation at late times. in enqvist et al. (2015), we mainly focused on the effects of decaying dark matter (ddm) on the cosmic microwave background (cmb) and nonlinear matter power spectrum. extending our previous analysis, here we use n-body simulation to investigate how ddm affects the halo mass function. this allows us to incorporate the cluster counts observed by the sunyaev-zel'dovich effect to study a bound on the lifetime of ddm . we also update the data of cmb and cosmic shear power spectrum with the planck 2015 results and kids450 observations, respectively. from these cosmological observations, we obtain an lower bound on the lifetime γ-1>= 154 gyr from the planck2015 results (cmb+sz cluster count) combined with the kids450 and the recent measurements of the baryon acoustic scale. | constraints on decaying dark matter from weak lensing and cluster counts |
we constrain the parameters of a representative new physics model with possible dark matter (dm) signature from a global ckm fit analysis. the model has neutral quark current interactions mediated by a scalar, impacting the semileptonic and purely leptonic meson decays at one-loop. we take this opportunity to update the fit results for the wolfenstein parameters and the ckm elements with and without a contribution from the new model using several other updated inputs. alongside, we have analyzed and included in the ckm fit the $b\to d^*\ell\nu_{\ell}$ decay. the newly available inputs on the relevant form factors from lattice are included, and the possibility of new physics effects in $b\to d^*\ell\nu_{\ell}$ is considered. we obtain tight constraints on the relevant new physics parameters. we have studied the possible implications of this constraint on dm phenomenology. apart from dm, the bounds are also applicable in other relevant phenomenological studies. | constraining new physics with possible dark matter signatures from a global ckm fit |
if the peccei-quinn symmetry is already broken during inflation, the decay constant fa of the axion can be in a wide region from 1011gev to 1018gev for the axion being the dominant dark matter. in this case, however, the axion causes the serious cosmological problem, isocurvature perturbation problem, which severely constrains the hubble parameter during inflation. the constraint is relaxed when peccei-quinn scalar field takes a large value ∼mp (planck scale) during inflation. in this letter, we point out that the allowed region of the decay constant fa is reduced to a rather narrow region for a given tensor-to-scalar ratio r when peccei-quinn scalar field takes ∼mp during inflation. for example, if the ratio r is determined as r ≳10-3 in future measurements, we can predict fa ≃ (0.1- 1.4) ×1012gev for domain wall number ndw = 6. | cosmologically allowed regions for the axion decay constant fa |
we show that a couplet, a pair of closely spaced photon lines, in the x-ray spectrum is a distinctive feature of lepton flavored dark matter models for which the mass spectrum is dictated by minimal flavor violation. in such a scenario, mass splittings between different dark matter flavors are determined by standard model yukawa couplings and can naturally be small, allowing all three flavors to be long-lived and contribute to the observed abundance. then, in the presence of a tiny source of flavor violation, heavier dark matter flavors can decay via a dipole transition on cosmological timescales, giving rise to three photon lines. two of these lines are closely spaced, and constitute the couplet. provided the flavor violation is sufficiently small, the ratios of the line energies are determined in terms of the charged lepton masses, and constitute a prediction of this framework. for dark matter masses of order the weak scale, the couplet lies in the kev-mev region, with a much weaker line in the ev-kev region. this scenario constitutes a potential explanation for the recent claim of the observation of a 3.5 kev line. the next generation of x-ray telescopes may have the necessary resolution to resolve the double line structure of such a couplet. | a couplet from flavored dark matter |
we perform numerical calculations of masses and decay constants of the lightest (flavoured) pseudoscalar, vector and axial vector mesons in the $sp(4)$ lattice gauge theory with three dirac fermions in the antisymmetric representation. the corresponding continuum theory plays an important role in certain ultra-violet complete realisations of composite higgs, partial top compositeness, and composite dark matter models. in addition, we measure the masses of other flavoured mesons in spin-$0$ and $1$ channels, as well as the first excited state of the vector mesons. using the gradient flow to set the scale, we carry out the continuum extrapolation and show preliminary results for the meson spectrum of the theory. | spectroscopy of sp(4) lattice gauge theory with n_f=3 antisymmetric fermions |
zinc tungstate (znwo4) crystal scintillators are promising detection material for the experiments searching for double beta decay, dark matter, and investigating rare alpha decays. an extended r&d was performed to develop advanced quality znwo4 crystal scintillators. the r&d programme included the selection of the initial materials, the variation of the compound stoichiometry, the application of single and double crystallization, and the annealing of the crystal boules. the optical transmittance of the produced boules was measured, and the luminescence under x-ray excitation in the temperature region from 85 k to room temperature was studied (thermally stimulated luminescence was measured till 350 k). the energy resolution and the relative scintillation pulse amplitude were measured with gamma-sources demonstrating high scintillation properties of the samples produced by single crystallization from deeply purified zinc and tungsten oxides, with stoichiometric composition, annealed in air atmosphere. | optical, luminescence, and scintillation properties of advanced znwo4 crystal scintillators |
we study how supersonic streaming velocities of baryons relative to dark matter-a large-scale effect imprinted at recombination and coherent over ~3 mpc scales-affect the formation of dwarf galaxies at z ≳ 5. we perform cosmological hydrodynamic simulations, including and excluding streaming velocities, in regions centered on halos with m vir(z = 0) ≈ 1010 m ⊙; the simulations are part of the feedback in realistic environments (fire) project and run with fire-3 physics. our simulations comprise many thousands of systems with halo masses between m vir = 2 × 105 m ⊙ and 2 × 109 m ⊙ in the redshift range z = 20-5. a few hundred of these galaxies form stars and have stellar masses ranging from 100 to 107 m ⊙. while star formation is globally delayed by approximately 50 myr in the streaming relative to nonstreaming simulations and the number of luminous galaxies is correspondingly suppressed at high redshift in the streaming runs, these effects decay with time. by z = 5, the properties of the simulated galaxies are nearly identical in the streaming versus nonstreaming runs, indicating that any effects of streaming velocities on the properties of galaxies at the mass scale of classical dwarfs and larger do not persist to z = 0. | dwarf galaxy formation with and without dark matter-baryon streaming velocities |
a search for long-lived particles decaying into muon pairs is performed using proton-proton collisions at a center-of-mass energy of 13 tev, collected by the cms experiment at the lhc in 2017 and 2018, corresponding to an integrated luminosity of 101 fb-1. the data sets used in this search were collected with a dedicated dimuon trigger stream with low transverse momentum thresholds, recorded at high rate by retaining a reduced amount of information, in order to explore otherwise inaccessible phase space at low dimuon mass and nonzero displacement from the primary interaction vertex. no significant excess of events beyond the standard model expectation is found. upper limits on branching fractions at 95% confidence level are set on a wide range of mass and lifetime hypotheses in beyond the standard model frameworks with the higgs boson decaying into a pair of long-lived dark photons, or with a long-lived scalar resonance arising from a decay of a b hadron. the limits are the most stringent to date for substantial regions of the parameter space. these results can be also used to constrain models of displaced dimuons that are not explicitly considered in this paper. | search for long-lived particles decaying into muon pairs in proton-proton collisions at √{s } = 13 tev collected with a dedicated high-rate data stream |
we investigate multi-lepton signals produced by electroweakino (ewino) decays in the mssm and the tmssm scenarios with sfermions, gluinos and non standard model higgses at the tev scale, with dark matter due to electroweak-scale binos. we recast the present lhc constraints on ewinos for these models and we find that wide mssm and tmssm parameter regions prove to be allowed. we forecast the number of events expected in the signal regions of the experimental multi-lepton analyses in the next lhc runs. the correlations among these numbers will help to determine whether future deviations in multi-lepton data are ascribable to the ewinos, as well as the supersymmetric model they originate from. | confronting susy models with lhc data via electroweakino production |
the singularity theorems of the 1960s showed that lemaître's initial symmetry assumptions were not essential for deriving a big-bang origin for a vast multitude of relativistic universe models. yet the actual universe accords remarkably closely with models of lemaître's type. this is a mystery closely related to the form taken by the 2nd law of thermodynamics and is not explained by currently conventional inflationary cosmology. conformal cyclic cosmology (ccc) provides another perspective on these issues, one consequence being the necessary initial presence of a dominant scalar material that interacts only gravitationally, but which must ultimately slowly decay away in a novel but perhaps detectable way. according to ccc, our current universe picture provides but one aeon of an unending succession of expanding aeons each having an initial big bang which is the conformal continuation of the remote exponential expansion of its previous aeon. the observational status of ccc is briefly discussed. | the big bang and its dark-matter content: whence, whither, and wherefore |
we investigate the einstein vacuum equations as well as the einstein-null fluid equations describing neutrino radiation. we find new structures in gravitational waves and memory for asymptotically-flat spacetimes of slow decay. these structures do not arise in spacetimes resulting from data that is stationary outside a compact set. rather the more general situations exhibit richer geometric-analytic interactions displaying the physics of these more general systems. it has been known that for stronger decay of the data gravitational wave memory is finite and of electric parity only. we investigate general spacetimes that are asymptotically flat in a rough sense, where the decay of the data to minkowski space towards infinity is very slow. main new feature: we prove that there exists diverging magnetic memory sourced by the magnetic part of the curvature tensor (a) in the einstein vacuum and (b) in the einstein-null-fluid equations. the magnetic memory occurs naturally in the einstein vacuum setting (a) of pure gravity. in case (b), in the ultimate class of solutions, the magnetic memory also contains a curl term from the energy-momentum tensor for neutrinos also diverging at the highest rate. the electric memory diverges too, it is generated by the electric part of the curvature tensor and in the einstein-null-fluid situation also by the corresponding energy-momentum component. in addition, we find a panorama of finer structures in these manifolds. some of these manifest themselves as additional contributions to both electric and magnetic memory. our theorems hold for any type of matter or energy coupled to the einstein equations as long as the data decays slowly towards infinity and other conditions are satisfied. the new results have many applications ranging from mathematical general relativity to gravitational wave astrophysics, detecting dark matter and other topics in physics. | new structures in gravitational radiation |
the experiment cresst-ii aims at the detection of dark matter with scintillating cawo4 crystals operated as cryogenic detectors. recent results on spin-independent wimp-nucleon scattering from the cresst-ii phase 2 allowed to probe a new region of parameter space for wimp masses below 3 gev/c2. this sensitivity was achieved after background levels were reduced significantly. we present extensive background studies of a cawo4 crystal, called tum40, grown at the technische universität münchen. the average beta/gamma rate of 3.51/[kg kev day] (1-40 kev) and the total intrinsic alpha activity from natural decay chains of 3.08±0.04 mbq/kg are the lowest reported for cawo4 detectors. contributions from cosmogenic activation, surface-alpha decays, external radiation and intrinsic alpha/beta emitters are investigated in detail. a monte-carlo based background decomposition allows to identify the origin of the majority of beta/gamma events in the energy region relevant for dark matter search. | beta/gamma and alpha backgrounds in cresst-ii phase 2 |
we investigate a quasi one-dimensional {{}87}\text{rb} bose-einstein condensate in a harmonic trap with an additional dimple trap (dt) in the center. within a zero-temperature gross-pitaevskii mean-field description we provide a one-dimensional physical intuitive model, which we solve by both a time-independent variational approach and numerical calculations. with this we obtain at first equilibrium results for the emerging condensate wave function which reveal that a dimple trap potential induces a bump or a dip in case of a red- or a blue-detuned gaussian laser beam, respectively. afterwards, we investigate how this dt induced bump/dip-imprint upon the condensate wave function evolves for two quench scenarios. at first we consider the generic case that the harmonic confinement is released. during the resulting time-of-flight expansion it turns out that the dt induced bump in the condensate wave function remains present, whereas the dip starts decaying after a characteristic time scale which decreases with increasing blue-detuned dt depth. secondly, once the red- or blue-detuned dt is switched off, we find that bright shock-waves or gray/dark bi-soliton trains emerge which oscillate within the harmonic confinement with a characteristic frequency. | statics and dynamics of quasi one-dimensional bose-einstein condensate in harmonic and dimple trap |
search for compressed supersymmetry at multi-tev scale, in the presence of a light gravitino dark matter, can get sizable uplift while looking into the associated fat- jets with missing transverse momenta as a signature of the boson produced in the decay process of much heavier next-to-lightest sparticle. we focus on the hadronic decay of the ensuing higgs and/or z boson giving rise to at least two fat-jets and [inline-graphic not available: see fulltext] in the final state. we perform a detailed background study adopting a multivariate analysis using a boosted decision tree to provide a robust investigation to explore the discovery potential for such signal at 14 tev lhc considering different benchmark points satisfying all the theoretical and experimental constraints. this channel provides the best discovery prospects with most of the benchmarks discoverable within an integrated luminosity of ℒ = 200 fb-1. kinematic observables are investigated in order to distinguish between compressed and uncompressed spectra having similar event yields. | boosted jet techniques for a supersymmetric scenario with gravitino lsp |
we show how to produce antideuteron, antihelium, and other antinuclei in large fractions from the decays of a new particle ϕ that carries baryon number. close to threshold, the production of nuclear bound states is preferred over the decay into individual nucleons, effectively decoupling antinuclei and antiproton fluxes and allowing the former to dominate, in clear contrast to antimatter production via coalescence. ϕ can either form dark matter itself or be produced by it, and can give rise to a potentially testable amount of antinuclei. | how to produce antinuclei from dark matter |
now 50 years since the existence of the neutron star crust was proposed, we review the current understanding of the nuclear physics of the outer layers of accreting neutron stars. nuclei produced during nuclear burning replace the nascent composition of the neutron star ocean and crust. non-equilibrium nuclear reactions driven by compression alter the outer thermal structure and chemical composition, leaving observable imprints on astronomical phenomena. as observations of bursting neutron stars and cooling neutron stars have increased, the recent volume of astronomical data allows new insights into the microphysics of the neutron star interior and the possibility to test nuclear physics input in model calculations. despite numerous advances in our understanding of neutron star interiors and observed neutron star phenomena, many challenges remain in the astrophysics theory of accreting neutron stars, the nuclear theory of neutron-rich nuclei, and the reach and precision of terrestrial nuclear physics experiments. | nuclear physics of the outer layers of accreting neutron stars |
ages and thermal luminosities of neutron stars, inferred from observations, can be interpreted with the aid of the neutron star cooling theory to gain information on the properties of superdense matter in neutron-star interiors. we present a survey of estimated ages, surface temperatures, and thermal luminosities of middle-aged neutron stars with relatively weak or moderately strong magnetic fields, which can be useful for these purposes. the catalogue includes results selected from the literature, supplemented with new results of spectral analysis of a few cooling neutron stars. the data are compared with the theory. we show that overall agreement of theoretical cooling curves with observations improves substantially for models where neutron superfluidity in stellar core is weak. | thermal luminosities of cooling neutron stars |
we suggest an extension to isospin asymmetric matter of the quarkyonic model from mclerran and reddy [phys. rev. lett. 122, 122701 (2019), 10.1103/physrevlett.122.122701]. this extension allows us to construct the β equilibrium between quarks, nucleons, and leptons. the concept of quarkyonic matter originates from the large number of color limit for which nucleons have the correct degrees of freedom near the fermi surface—reflecting the confining forces—while deep inside the fermi sea quarks appear naturally. in isospin-asymmetric matter, we suggest to implement this concept within a global isoscalar relation between the shell gaps differentiating the nucleon and the quark sectors. in addition, we impose the conservation of the isospin-flavor asymmetry for the nucleon and the quark components. within this model, several quarkyonic stars are constructed on top of the sly4 model for the nucleon sector, producing a bump in the sound speed. as a consequence, quarkyonic stars are systematically bigger and have a larger maximum mass than the associated neutron stars. this model also predicts a lower proton fraction at β equilibrium, which potentially quenches fast cooling in massive compact stars. | quarkyonic stars with isospin-flavor asymmetry |
the observed rapid cooling of the cassiopeia a neutron star can be interpreted as being caused by neutron and proton transitions from normal to superfluid and superconducting states in the stellar core. here we present two new chandra acis-s graded observations of this neutron star and measurements of the neutron star mass m and radius r found from consistent fitting of both the x-ray spectra and cooling behavior. this comparison is only possible for individual nuclear equations of state. we test phenomenological superfluid and superconducting gap models which mimic many of the known theoretical models against the cooling behavior. our best-fit solution to the cassiopeia a data is one in which the (m ,r ) =(1.44 msun,12.6 km) neutron star is built with the bsk21 equation of state, strong proton superconductor and moderate neutron triplet superfluid gap models, and a pure iron envelope or a thin carbon layer on top of an iron envelope, although there are still large observational and theoretical uncertainties. | tests of the nuclear equation of state and superfluid and superconducting gaps using the cassiopeia a neutron star |
pairing gaps in neutron matter need to be computed in a wide range of densities to address open questions in neutron-star phenomenology. traditionally, the bardeen-cooper-schrieffer approach has been used to compute gaps from bare nucleon-nucleon interactions. here we incorporate the influence of short- and long-range correlations in the pairing gaps. short-range correlations are treated, including the appropriate fragmentation of single-particle states, and substantially suppress the gaps. long-range correlations dress the pairing interaction via density and spin modes and provide a relatively small correction. we use different interactions, some with three-body forces, as a starting point to control for any systematic effects. results are relevant for neutron-star cooling scenarios, in particular in view of the recent observational data on cassiopeia a. | pairing in high-density neutron matter including short- and long-range correlations |
in the present work we apply non-extensive statistics to obtain equations of state suitable to describe stellar matter and verify its effects on microscopic and macroscopic quantities. two snapshots of the star evolution are considered and the direct urca process is investigated with two different parameter sets. q-values are chosen as 1.05 and 1.14. the equations of state are only slightly modified, but the effects are enough to produce stars with slightly higher maximum masses. the onsets of the constituents are more strongly affected and the internal stellar temperature decreases with the increase of the q-value, with consequences on the strangeness and cooling rates of the stars. | non-extensive thermodynamics and neutron star properties |
we study the axion cooling of neutron stars within the dine-fischler-srednicki-zhitnitsky (dfsz) model, which allows for tree-level coupling of electrons to the axion and locks the peccei-quinn charges of fermions via an angle parameter. this extends our previous study [phys. rev. d 93, 065044 (2016), 10.1103/physrevd.93.065044] limited to hadronic models of axions. we explore the two-dimensional space of axion parameters within the dfsz model by comparing the theoretical cooling models with the surface temperatures of a few stars with measured surface temperatures. it is found that axions masses ma≥0.06 to 0.12 ev can be excluded by x-ray observations of thermal emission of neutron stars (in particular by those of cas a), the precise limiting value depending on the angle parameter of the dfsz model. it is also found that axion emission by electron bremsstrahlung in neutron star crusts is negligible except for the special case where neutron peccei-quinn charge is small enough, so that the coupling of neutrons to axions can be neglected. | axion cooling of neutron stars. ii. beyond hadronic axions |
we demonstrate that in the framework of standard general relativity, polytropic spheres with properly fixed polytropic index n and relativistic parameter σ , giving a ratio of the central pressure pc to the central energy density ρc , can contain a region of trapped null geodesics. such trapping polytropes can exist for n >2.138 , and they are generally much more extended and massive than the observed neutron stars. we show that in the n - σ parameter space, the region of allowed trapping increases with the polytropic index for intervals of physical interest, 2.138 <n <4 . space extension of the region of trapped null geodesics increases with both increasing n and σ >0.677 from the allowed region. in order to relate the trapping phenomenon to astrophysically relevant situations, we restrict the validity of the polytropic configurations to their extension rextr corresponding to the gravitational mass m ∼2 m⊙ of the most massive observed neutron stars. then, for the central density ρc∼1 015 g cm-3 , the trapped regions are outside rextr for all values of 2.138 <n <4 ; for the central density ρc∼5 ×1 015 g cm-3 , the whole trapped regions are located inside rextr for 2.138 <n <3.1 ; while for ρc∼1 016 g cm-3 , the whole trapped regions are inside rextr for all values of 2.138 <n <4 , guaranteeing astrophysically plausible trapping for all considered polytropes. the region of trapped null geodesics is located close to the polytrope center and could have a relevant influence on the cooling of such polytropes or binding of gravitational waves in their interior. | polytropic spheres containing regions of trapped null geodesics |
a set of unified relativistic mean-field equations of state for hyperonic compact stars recently built in [m. fortin, ad. r. raduta, s. avancini, and c. providência, phys. rev. d 101, 034017 (2020), 10.1103/physrevd.101.034017] is used to study the thermal evolution of nonmagnetized and nonrotating spherically-symmetric isolated and accreting neutron stars under different hypothesis concerning proton s -wave superfluidity. these equations of state have been obtained in the following way: the slope of the symmetry energy is in agreement with experimental data; the coupling constants of λ and ξ -hyperons are determined from experimental hypernuclear data; uncertainties in the nucleon-σ interaction potential are accounted for; current constraints on the lower bound of the maximum neutron star mass are satisfied. within the considered set of equations of state, the presence of hyperons is essential for the description of the cooling/heating curves. one of the conclusions we reach is that the criterion of best agreement with observational data leads to different equations of states and proton s -wave superfluidity gaps when applied separately for isolated neutron stars and accreting neutron stars in quiescence. this means that at least in one situation the traditional simulation framework that we employ is not complete and/or the equations of state are inappropriate. another result is that, considering equations of state which do not allow for nucleonic durca or allow for it only in very massive ns, the low luminosity of sax j1808 requires a repulsive σ -hyperon potential in symmetric nuclear matter in the range uσ(n )≈10 - 30 mev . this range of values for uσ(n ) is also supported by the criterion of best agreement with all available data from ins and xrt. | thermal evolution of relativistic hyperonic compact stars with calibrated equations of state |
quantum metrology exploits quantum correlations to make precise measurements with limited particle numbers. by utilizing inter- and intramode correlations in an optical interferometer, we find a state that combines entanglement and squeezing to give a sevenfold enhancement in the quantum fisher information (qfi)—a metric related to the precision—over the shot-noise limit, for low photon numbers. motivated by practicality we then look at the squeezed cat state, which has recently been made experimentally, and shows further precision gains over the shot-noise limit and a threefold improvement in the qfi over the optimal gaussian state. we present a conceptually simple measurement scheme that saturates the qfi, and we demonstrate a robustness to loss for small photon numbers. the squeezed cat state can therefore give a significant precision enhancement in optical quantum metrology in practical and realistic conditions. | practical quantum metrology with large precision gains in the low-photon-number regime |
the standard cooling scenario in the presence of nucleon superfluidity fits rather well to the observation of the neutron stars. it implies that the stellar cooling arguments could place a stringent constraint on the properties of novel particles. we study in particular the cooling rate induced by dark gauge bosons for very young neutron stars: remnants of cassiopeia a and sn1987a. the cooling is dominantly contributed either by the nucleon pair breaking and formation in the core or by the electron bremsstrahlung in the crust, depending on the age of the stars and the form of the couplings. we compute how much the cooling curve of the young neutron stars could be modified by the extra dark gauge boson emission and obtain the bound for the dark gauge boson when its mass is lower than o (0.1 ) mev ; for the dark photon, we find the mixing parameter times its mass ϵ mγ'<1.5 ×10-8 mev and for the u (1 )b-l gauge boson its coupling to nucleons and electrons e'<5 ×10-13. we also discuss the possibility that the rapid cooling of cas a might provide a hint for the existence of the u (1 )b-l gauge boson of mass around ev and its coupling e'∼10-13. | cooling of young neutron stars and dark gauge bosons |
we conduct a comprehensive survey of the shape parameter space of the nuclear pasta phases in neutron star crusts by conducting three-dimensional hartree-fock +bcs calculations. spaghetti, waffles, lasagna, bicontinuous phases and cylindrical holes occupy local minima in the resulting constant-pressure gibbs energy surfaces, implying multiple geometries coexist at a given depth. notably, the bicontinuous phase, in which both the neutron gas and nuclear matter extend continuously in all dimensions appears over a large depth range. our results support the idea that nuclear pasta is a glassy system. at a characteristic temperature, of order 108-109k , different phases may become frozen into domains whose sizes we estimate to be 1-50 times the lattice spacing and over which the local density and electron fraction can vary. above this temperature, very little long-range order exists and matter is an amorphous solid. electron scattering off domain boundaries may contribute to the disorder resistivity of the pasta phases. annealing of the domains may occur during cooling; repopulating of local minima during crustal heating might lead to temperature-dependent transport properties in the deep crust layers. we identify four regions distinguished by whether pasta is the true ground state, and whether the pasta structure allows delocalization of protons. the whole pasta region can occupy up to 70% of the crust by mass and 25% by thickness, and the layer in which protons are delocalized could occupy 45% of the crust mass and 15% of its thickness. | glassy quantum nuclear pasta in neutron star crusts |
we perform cooling simulations for isolated neutron stars using recently developed equations of state for their core. the equations of state are obtained from new parametrizations of the fsu2 relativistic mean-field functional that reproduce the properties of nuclear matter and finite nuclei, while fulfilling the restrictions on high-density matter deduced from heavy-ion collisions, measurements of massive 2 m ⊙ neutron stars, and neutron star radii below 13 km. we find that two of the models studied, fsu2r (with nucleons) and in particular fsu2h (with nucleons and hyperons), show very good agreement with cooling observations, even without including extensive nucleon pairing. this suggests that the cooling observations are more compatible with an equation of state that produces a soft nuclear symmetry energy, hence it generates small neutron star radii. however, both models favor large stellar masses, above 1.8 m ⊙, to explain the colder isolated neutron stars that have been observed, even if nucleon pairing is present. | cooling of small and massive hyperonic stars |
x-ray emission from the surface of isolated neutron stars (nss) has been now observed in a variety of sources. the ubiquitous presence of pulsations clearly indicates that thermal photons either come from a limited area, possibly heated by some external mechanism, or from the entire (cooling) surface but with an inhomogeneous temperature distribution. in an ns the thermal map is shaped by the magnetic field topology since heat flows in the crust mostly along the magnetic field lines. self-consistent surface thermal maps can hence be produced by simulating the coupled magnetic and thermal evolution of the star. we compute the evolution of the ns crust in three dimensions for different initial configurations of the magnetic field and use the ensuing thermal surface maps to derive the spectrum and the pulse profile as seen by an observer at infinity, accounting for general-relativistic effects. in particular, we compare cases with a high degree of symmetry with inherently 3d ones, obtained by adding a quadrupole to the initial dipolar field. axially symmetric fields result in rather small pulsed fractions (≲5%), while more complex configurations produce higher pulsed fractions, up to ~25%. we find that the spectral properties of our axisymmetric model are close to those of the bright isolated ns rx j1856.5-3754 at an evolutionary time comparable with the inferred dynamical age of the source. | x-ray emission from isolated neutron stars revisited: 3d magnetothermal simulations |
central compact objects (ccos) are young neutron stars emitting thermal x-rays with bolometric luminosities lx in the range of 1032-1034 erg s-1. gourgouliatos, hollerbach, and igoshev recently suggested that peculiar emission properties of ccos can be explained by tangled magnetic field configurations formed in a stochastic dynamo during the proto-neutron star stage. in this case the magnetic field consists of multiple small-scale components with negligible contribution of global dipolar field. we study numerically three-dimensional magnetothermal evolution of tangled crustal magnetic fields in neutron stars. we find that all configurations produce complicated surface thermal patterns that consist of multiple small hot regions located at significant separations from each other. the configurations with initial magnetic energy of (2.5-10) × 1047 erg have temperatures of hot regions that reach ≈ 0.2 kev, to be compared with the bulk temperature of ≈ 0.1 kev in our simulations with no cooling. a factor of two in temperature is also seen in observations of ccos. the hot spots produce periodic modulations in light curve with typical amplitudes of ≤9%-11%. therefore, the tangled magnetic field configuration can explain thermal emission properties of some ccos. | 3d magnetothermal simulations of tangled crustal magnetic field in central compact objects |
we demonstrate that the existing neutron-star cooling data can be appropriately described within "the nuclear medium cooling scenario" including hyperons under the assumption that different compact-star sources have different masses. we use a stiff equation of state of the relativistic mean-field model mkvorhϕ with hadron effective couplings and masses dependent on the scalar field. it fulfills a large number of experimental constraints on the equation of state of the nuclear matter including the 2m⊙ lower bound for the maximum compact-star mass and the constraint for the pressure from the heavy-ion particle flow. we select appropriate s10 proton and λ hyperon pairing gap profiles from those exploited in the literature and allow for a variation of the effective pion gap controlling the efficiency of the medium modified urca process. the p32 neutron pairing gap is assumed to be negligibly small in our scenario. the possibility of the pion, kaon and charged ρ-meson condensations is for simplicity suppressed. the resulting cooling curves prove to be sensitive to the value and the density dependence of the pp pairing gap and rather insensitive to the values of the s10 neutron pairing gaps. | cooling of neutron stars in "nuclear medium cooling scenario" with stiff equation of state including hyperons |
the direct urca process of rapid neutrino emission can occur in nonuniform nuclear pasta phases that are expected in the inner crusts of neutron stars. here, the periodic potential for a nucleon in nuclear pasta allows momentum conservation to be satisfied for direct urca reactions. we improve on earlier work by modeling a rich variety of pasta phases (gnocchi, waffle, lasagna, and anti-spaghetti) with large-scale molecular dynamics simulations. we find that the neutrino luminosity due to direct urca reactions in nuclear pasta can be 3 to 4 orders of magnitude larger than that from the modified urca process in the ns core. thus neutrino radiation from pasta could dominate radiation from the core and this could significantly impact the cooling of neutron stars. | fast neutrino cooling of nuclear pasta in neutron stars: molecular dynamics simulations |
we investigate the evolution of the chiral magnetic instability in a protoneutron star and compute the resulting magnetic power and helicity spectra. the instability may act during the early cooling phase of the hot protoneutron star after supernova core collapse, where it can contribute to the buildup of magnetic fields of strength up to the order of 1014 g. the maximal field strengths generated by this instability, however, depend considerably on the temperature of the protoneutron star, on density fluctuations and turbulence spectrum of the medium. at the end of the hot cooling phase the magnetic field tends to be concentrated around the submillimeter to cm scale, where it is subject to slow resistive damping. | chiral magnetic effect in protoneutron stars and magnetic field spectral evolution |
we present the mass excesses of cr-6459, obtained from recent time-of-flight nuclear mass measurements at the national superconducting cyclotron laboratory at michigan state university. the mass of 64cr is determined for the first time, with an atomic mass excess of -33.48 (44 ) mev. we find a significantly different two-neutron separation energy s2 n trend for neutron-rich isotopes of chromium, removing the previously observed enhancement in binding at n =38 . additionally, we extend the s2 n trend for chromium to n =40 , revealing behavior consistent with the previously identified island of inversion in this region. we compare our results to state-of-the-art shell-model calculations performed with a modified lenzi-nowacki-poves-sieja interaction in the f p shell, including the g9 /2 and d5 /2 orbits for the neutron valence space. we employ our result for the mass of 64cr in accreted neutron star crust network calculations and find a reduction in the strength and depth of electron-capture heating from the a =64 isobaric chain, resulting in a cooler than expected accreted neutron star crust. this reduced heating is found to be due to the >1 -mev reduction in binding for 64cr with respect to values from commonly used global mass models. | time-of-flight mass measurements of neutron-rich chromium isotopes up to n =40 and implications for the accreted neutron star crust |
we present mass excesses (me) of neutron-rich isotopes of ar through fe, obtained via time of flight b ρ mass spectrometry at the national superconducting cyclotron laboratory. our new results have significantly reduced systematic uncertainties relative to a prior analysis, enabling the first determination of me for ti,5958,62v,65cr,mn,6867, and fe,7069. our results show the n =34 subshell weaken at sc and vanish at ti, along with the absence of an n =40 subshell at mn. this leads to a cooler accreted neutron star crust, highlighting the connection between the structure of nuclei and neutron stars. | nuclear mass measurements map the structure of atomic nuclei and accreting neutron stars |
nucleon effective masses are studied in the framework of the brueckner-hartree-fock many-body approach at finite temperature. self-consistent calculations using the argonne v18 interaction including a microscopic three-body force are reported for varying temperature and proton fraction up to several times the nuclear saturation density. our calculations are based on the exact treatment of the center-of-mass momentum instead of the average-momentum approximation employed in previous works. we discuss in detail the effects of the temperature together with those of the three-body force, the density, and the isospin asymmetry. we also provide an analytical fit of the effective mass taking these dependencies into account. the temperature effects on the cooling of neutron stars are briefly discussed based on the results for β -stable matter. | nucleon effective mass in hot dense matter |
axion-like particles are predicted in many physics scenarios beyond the standard model (sm). their interactions with sm particles may arise from the triangle anomaly of the associated global symmetry, along with other sm global and gauge symmetries, including anomalies with the global baryon number and electromagnetic gauge symmetries. we initiate the phenomenological study of the corresponding ``electrobaryonic axion", a particle that couples with both the baryon chemical potential and the electromagnetic field. neutron stars, particularly magnetars, possessing high baryon density and strong magnetic fields, can naturally develop a thin axion hair around their surface. in this study, we calculate this phenomenon, considering the effects of neutron star rotation and general relativity. for axion particles lighter than the neutron star rotation frequency, the anomalous interaction can also induce the emission of axion particles from the neutron star. this emission, in the light axion regime, can have a significant contribution to the neutron star cooling rate. | electrobaryonic axion: hair of neutron stars |
we investigate the nuclear symmetry energy and neutron star properties using a bayesian analysis based on constraints from different chiral effective field theory calculations using new energy density functionals that allow for large variations at high densities. constraints at high densities are included from observations of gw170817 and nicer. in particular, we show that both nicer analyses lead to very similar posterior results for the symmetry energy and neutron star properties when folded into our equation of state framework. using the posteriors, we provide results for the symmetry energy and the slope parameter, as well as for the proton fraction, the speed of sound, and the central density in neutron stars. moreover, we explore correlations of neutron star radii with the pressure and the speed of sound in neutron stars. our 95\% credibility ranges for the symmetry energy $s_v$, the slope parameter $l$, and the radius of a 1.4\,$m_\odot$ neutron star $r_{1.4}$ are $s_v=(30.6-33.9)$\,mev, $l=(43.7-70.0)$\,mev, and $r_{1.4}=(11.6-13.2)$\,km. our analysis for the proton fraction shows that larger and-or heavier neutron stars are more likely to cool rapidly via the direct urca process. within our equation of state framework a maximum mass of neutron stars $m_{\rm max}>2.1\,m_\odot$ indicates that the speed of sound needs to exceed the conformal limit. | symmetry energy and neutron star properties constrained by chiral effective field theory calculations |
we study the oscillations of relativistic stars, incorporating key physics associated with internal composition, thermal gradients and crust elasticity. our aim is to develop a formalism which is able to account for the state-of-the-art understanding of the complex physics associated with these systems. as a first step, we build models using a modern equation of state including composition gradients and density discontinuities associated with internal phase transitions (like the crust-core transition and the point where muons first appear in the core). in order to understand the nature of the oscillation spectrum, we carry out cooling simulations to provide realistic snapshots of the temperature distribution in the interior as the star evolves through adolescence. the associated thermal pressure is incorporated in the perturbation analysis, and we discuss the presence of g -modes arising as a result of thermal effects. we also consider interface modes due to phase-transitions and the gradual formation of the star's crust and the emergence of a set of shear modes. | seismology of adolescent neutron stars: accounting for thermal effects and crust elasticity |
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