Future Dark Matter Direct Detection Research Articles

Explaining the W boson mass anomaly and dark matter with a U(1) dark sector* *WZF is supported in part by the National Natural Science Foundation of China (11905158, 11935009) and the Natural Science Foundation of Tianjin City (20JCQNJC02030).

The W boson mass recently reported by the CDF collaboration shows a deviation from the standard model prediction with an excess at the level. We investigate two simple extensions of the standard model with an extra dark sector. One is the extension, where the gauge field mixes with the standard model through gauge kinetic terms. The other is a general extension of the standard model. Fitting various experimental constraints, we find that the extension with only kinetic mixing can enhance the W boson mass by 10 MeV at most. Theextension can easily generate a 77 MeV enhancement of the W boson mass and also offer a viable dark matter candidate with a mass ranging from several hundred GeV to TeV, which may be detected by future dark matter direct detection experiments with improved sensitivities.

Probing neutrino magnetic moments and the Xenon1T excess with coherent elastic solar neutrino scattering

The detection potential of the active neutrino magnetic moment ($\nu_{a}$MM) and the active sterile transition magnetic moment ($\nu_{s}$MM) of the solar neutrino CE$\nu$NS process in future Dark Matter direct detection experiments is studied and compared with the respective allowed range to explain the Xenon1T excess. We find that the sensitivity to the $\nu_{a}$MM approaches to the level between $10^{-10}\mu_B$ and $10^{-11}\mu_B$, which is dominantly limited by the detection threshold. On the other hand, the future solar neutrino CE$\nu$NS detection would be powerful in probing the $\nu_{s}$MM for the sterile neutrino mass below 10 MeV, which could unambiguously test the $\nu_{s}$MM explanation of the Xenon1T excess. The sensitivity in the general framework with both $\nu_{a}$MM and $\nu_{s}$MM contributions is also derived.

Capture of electroweak multiplet dark matter in neutron stars

If dark matter has a sizable scattering cross section with nucleons, it can efficiently be captured by a neutron star. Its energy is then transferred to the neutron star as heat through the scattering and annihilation inside the star. This heating effect may be detectable via dedicated temperature observations of nearby old pulsars, providing an alternative method for dark matter searches. In this paper, we show that for electroweak multiplet dark matter this search strategy can probe the parameter region which is out of reach of future dark matter direct detection experiments. To see this systematically, we classify such dark matter candidates in terms of their electroweak charges and investigate the effect of ultraviolet physics by means of higher-dimensional effective operators. We then show that if the effect of ultraviolet physics is sizable, the dark matter-nucleon elastic scattering cross section becomes sufficiently large, whilst if it is suppressed, then the mass splittings among the components of the DM multiplet get small enough so that the inelastic scattering processes are operative. In any case, the electroweak multiplet dark matter particles are efficiently captured in neutron stars, making the search strategy with the temperature observation of old neutron stars promising.

The ASTAROTH Project: enhanced low-energy sensitivity to Dark Matter annual modulation

ASTAROTH is a novel R&D project which aims at improving the physics reach of future direct dark matter detection experiments based on NaI(Tl) scintillating crystals. There is a strong need to test the long standing DAMA positive observation of an annual modulation that could be due to Dark Matter (DM), with the same target material and in a model independent way. ASTAROTH aim is the enhancement of the sensitivity to the annual modulation signal, compared with present technology, by lowering the detection energy threshold in order to observe sub-keV recoils for the first time. This can be achieved by reading the scintillation light from the NaI(Tl) crystals with arrays of Silicon PhotoMultipliers (SiPM), and placing the detectors in a cryogenic environment. SiPMs feature lower dark noise than Photomultiplier Tubes (PMTs) at T < 150 K and allow for higher light collection. The cooling medium is liquid Argon, as it is an excellent scintillator that can be instrumented to act as a veto against several backgrounds.Here we present the status of the ASTAROTH project, introducing the innovative design of the detector chamber that will be used for the demonstration of the technology. Then, we will show the preliminary results of our first ever measurements performed on a single NaI(Tl) crystal read out by one SiPM array in a cryogenic set-up cooled with liquid nitrogen.

Direct detection of pseudo-Nambu-Goldstone dark matter with light mediator

It has been found that a pseudo-Nambu-Goldstone boson dark matter suppresses the amplitude for elastic scattering with nuclei in non-relativistic limit, and thus can naturally evade the strong constraint of dark matter direct detection experiments. In this paper, we show that non-zero elastic scattering cross section can be induced if the mediator mass is as small as momentum transfer. The predicted recoil energy spectrum can differ from that for usual thermal dark matter. Together with the relevant constraints such as thermal relic abundance, indirect detection and Higgs decays, we investigate the detectability through the current and future dark matter direct detection experiments.

Complementarity between dark matter direct searches and CE\u03bdNS experiments in U(1)\u2032 models

We explore the possibility of having a fermionic dark matter candidate within U(1)′ models for CEνNS experiments in light of the latest COHERENT data and the current and future dark matter direct detection experiments. A vector-like fermionic dark matter has been introduced which is charged under U(1)′ symmetry, naturally stable after spontaneous symmetry breaking. We perform a complementary investigation using CEνNS experiments and dark matter direct detection searches to explore dark matter as well as Z′ boson parameter space. Depending on numerous other constraints arising from the beam dump, LHCb, BABAR, and the forthcoming reactor experiment proposed by the SBC collaboration, we explore the allowed region of Z′ portal dark matter.

Natural Twin Neutralino Dark Matter.

Supersymmetric twin Higgs models have a discrete symmetry for which each standard model particle and its supersymmetric partner have a corresponding state that transforms under a mirror standard model gauge group. This framework is able to accommodate the nondiscovery of new particles at the LHC with the naturalness of the electroweak scale. We point out that supersymmetric twin Higgs models also provide a natural dark matter candidate. We investigate the possibility that a twin binolike state is the lightest supersymmetric particle and find that its freeze-out abundance can explain the observed dark matter abundance without fine-tuning the mass spectrum of the theory. Most of the viable parameter space can be probed by future dark matter direct detection experiments, and the LHC searches for staus and Higgsinos which may involve displaced vertices.

The current status of fine-tuning in supersymmetry

In this paper, we minimize and compare two different fine-tuning measures in four high-scale supersymmetric models that are embedded in the MSSM. In addition, we determine the impact of current and future dark matter direct detection and collider experiments on the fine-tuning. We then compare the low-scale electroweak measure with the high-scale Barbieri-Giudice measure. We find that they reduce to the same value when the higgsino parameter drives the degree of fine-tuning. We also find spectra where the high-scale measure turns out to be lower than the low-scale measure. Depending on the high-scale model and fine-tuning definition, we find a minimal fine-tuning of 3–38 (corresponding to O(10–1)%) for the low-scale measure, and 63–571 (corresponding to O(1–0.1)%) for the high-scale measure. We stress that it is too early to conclude on the fate of supersymmetry, based only on the fine-tuning paradigm.

Neutron EDM constrains direct dark matter detection prospects

A non-relativistic effective field theory (NREFT) offers a bottom-up framework to classify Dark Matter (DM) – nucleon interactions relevant for scattering at direct detection experiments by organizing the interactions in powers of the momentum transfer q→ and DM velocity v→. This approach generates a number of operators including P-odd and T-odd operators; these can only be generated from a relativistic theory with CP violating interactions. We consider the leading order P-odd, T-odd operators viz. O10, O11 and O12 and compare the constraints on these operators from leading direct detection searches and from the bound on the neutron EDM (nEDM). We perform our analysis using simplified models with charged mediators and compute the loop diagrams contributing to the nEDM. We find that constraints on the DM scattering cross section from the bound on the nEDM are several orders of magnitude stronger than the limits from direct searches, and even well below the neutrino floor for such NREFT operators, for the entire sub-GeV to TeV DM mass range. We conclude that one may not need to consider these operators when analyzing data from present or future direct dark matter detection experiments.

ν’s in Particle Physics and Cosmology

We propose a minimal scale-invariant (SI) scotogenic model and study its phenomenological implications. The SI scotogenic predicts a singlet scalar (dilaton) that triggers electroweak symmetry breaking and sources the lepton number violation that allows radiative neutrino mass. A viable parameter space is found for dark matter candidate and the observed neutrino oscillation. The model can be probed in lepton flavor violating processes, future dark matter direct detection experiments, and collider searches.

Detecting CNO solar neutrinos in next-generation xenon dark matter experiments

We study the prospects for measuring the low-energy components of the solar neutrino flux in future direct dark matter detection experiments. We show that for a depletion of $^{136}$Xe by a factor of 100 relative to its natural abundance, and an extension to electron recoil energies of $\sim$ MeV, future xenon experiments with exposure $\sim 200$ ton-yr can detect the CNO component of the solar neutrino flux at $\sim 3 \sigma$ significance. A CNO detection will provide important insight into metallicity of the solar interior. Precise measurement of low-energy solar neutrinos, including as $pp$, $^7$Be, and $pep$ components, will further improve constraints on the "neutrino luminosity" of the Sun, thereby providing constraints on alternative sources of energy production. We find that a measurement of $L_{\nu}/L_{\odot}$ of order one percent is possible with the above exposure, improving on current bounds from a global analysis of solar neutrino data by a factor of about seven.

Casting a wide signal net with future direct dark matter detection experiments

As dark matter (DM) direct detection experiments continue to improve their sensitivity they will inevitably encounter an irreducible background arising from coherent neutrino scattering. This so-called “neutrino floor” may significantly reduce the sensitivity of an experiment to DM-nuclei interactions, particularly if the recoil spectrum of the neutrino background is approximately degenerate with the DM signal. This occurs for the conventionally considered spin-independent (SI) or spin-dependent (SD) interactions. In such case, an increase in the experiment's exposure by multiple orders of magnitude may not yield any significant increase in sensitivity. The typically considered SI and SD interactions, however, do not adequately reflect the whole landscape of the well-motivated DM models, which includes other interactions. Since particle DM has not been detected yet in laboratories, it is essential to understand and maximize the detection capabilities for a broad variety of possible models and signatures. In this work we explore the impact of the background arising from various neutrino sources on the discovery potential of a DM signal for a large class of viable DM-nucleus interactions and several potential futuristic experimental settings, with different target elements. For some momentum suppressed cross sections, large DM particle masses and heavier targets, we find that there is no suppression of the discovery limits due to neutrino backgrounds. Further, we explicitly demonstrate that inelastic scattering, which could appear in models with multicomponent dark sectors, would help to lift the signal degeneracy associated with the neutrino floor. This study could assist with mapping out the optimal DM detection strategy for the next generation of experiments.

Naturally occurring 32Si and low-background silicon dark matter detectors

The naturally occurring radioisotope 32Si represents a potentially limiting background in future dark matter direct-detection experiments. We investigate sources of 32Si and the vectors by which it comes to reside in silicon crystals used for fabrication of radiation detectors. We infer that the 32Si concentration in commercial single-crystal silicon is likely variable, dependent upon the specific geologic and hydrologic history of the source (or sources) of silicon “ore” and the details of the silicon-refinement process. The silicon production industry is large, highly segmented by refining step, and multifaceted in terms of final product type, from which we conclude that production of 32Si-mitigated crystals requires both targeted silicon material selection and a dedicated refinement-through-crystal-production process. We review options for source material selection, including quartz from an underground source and silicon isotopically reduced in 32Si. To quantitatively evaluate the 32Si content in silicon metal and precursor materials, we propose analytic methods employing chemical processing and radiometric measurements. Ultimately, it appears feasible to produce silicon detectors with low levels of 32Si, though significant assay method development is required to validate this claim and thereby enable a quality assurance program during an actual controlled silicon-detector production cycle.

Non-standard interactions of solar neutrinos in dark matter experiments

We show that non-standard neutrino interactions (NSI) can be probed in future direct dark matter detection experiments through both elastic neutrino-electron scattering and coherent neutrino-nucleus scattering. We show NSI can increase the event rate due to solar neutrinos, with a sharp increase for lower nuclear recoil energy thresholds. We also identify an interference range of NSI parameters for which the rate is reduced by approximately 40%. Finally, we show that the “dark side” solution for the solar neutrino mixing angle may be discovered at forthcoming experiments.

Implications of heavy neutralino dark matter: The underlying structure in the hidden sector

The possibility of heavy neutralino dark matter (DM) in the gravity-mediation mechanism is explored. The appearance of the heavy lightest supersymmetric particle is seemingly suggested by Large Hadron Collider runs, which have not provided evidence of superparticles around the TeV region. On the basis of the so-called WIMPZILLA scenario, it is understood that the nonthermally produced DM has the larger mass than the reheating temperature. Hence, the expected DM mass should be more than 109 GeV so that thermal leptogenesis successfully occurs. In this paper, we first examine the generation of the Higgsino mass parameter [Formula: see text] in the context of gravity mediation, postulating that the resolution of the strong CP problem should be the criterion for arriving at a valid hypothesis for heavy neutralino DM. Accordingly, we address how the Peccei–Quinn (PQ) symmetry could influence dynamical supersymmetry breaking (DSB) models. It is found that as long as [Formula: see text] (the SUSY-breaking scale) approximately coincides with [Formula: see text] (the PQ-breaking scale), no DSB models can naturally account for the existence of the heavy neutralino DM, based upon the supersymmetric Dine–Fischler–Srednicki–Zhitinitski (DFSZ)-like mechanism. Thus, we attempt to construct a new model wherein hierarchical SUSY breakings occur. For this purpose, we propose gauge coupling unification in the hidden-sector dynamics at some high-energy scale, and we show that such a class of models can achieve [Formula: see text] through renormalization flow. As a consequence, the nonthermal neutralino, practically the wino-like one in our model, is shown to be a rather natural and viable DM candidate. Moreover, we argue that on the basis of Kac–Moody algebra, multiple breakdowns of supersymmetry may entail unified gauge dynamics. We also present a possible unified model. Finally, the heavy wino-like neutralino may be a DM candidate that will favor future direct DM detection experiments, mainly because its scattering on nuclei well conserves isospin symmetry.

WIMP dark matter in a well-tempered regime — A case study on singlet-doublets fermionic WIMP

Serious searches for the weakly interacting massive particle (WIMP) have now begun. In this context, the most important questions that need to be addressed are: "To what extent can we constrain the WIMP models in the future?" and "What will then be the remaining unexplored regions in the WIMP parameter space for each of these models?" In our quest to answer these questions, we classify WIMP in terms of quantum number and study each case adopting minimality as a guiding principle. As a first step, we study one of the simple cases of the minimal composition in the well-tempered fermionic WIMP regime, namely the singlet-doublets WIMP model. We consider all available constraints from direct and indirect searches and also the predicted constraints coming from the near future and the future experiments. We thus obtain the current status, the near future prospects and the future prospects of this model in all its generality. We find that in the future, this model will be constrained almost solely by the future direct dark matter detection experiments (as compared to the weaker indirect and collider constraints) and the cosmological (relic density) constraints and will hence be gradually pushed to the corner of the coannihilation region, if no WIMP signal is detected. Future lepton colliders will then be useful in exploring this region not constrained by any other experiments.

The galactic center excess from ℤ 3 $$ {\mathbb{Z}}_3 $$ scalar semi-annihilations

We investigate the possibility of the Z3 scalar singlet model explaining the Fermi galactic centre excess. We find a good fit to the measured spectral excess in the region where the dark matter mass is comparable to the Higgs and the Higgs portal coupling $\lambda_{HS}\sim 0.04$. This preferred region is consistent with constraints from vacuum stability and current dark matter experiments, and will be discovered or falsified soon by future dark matter direct detection experiment.

Dark matter, LFV and neutrino magnetic moment in the radiative seesaw model with fermion triplet

In this paper we work in the framework of a radiative seesaw model with triplet fermion Σ. Due to the Z2 discrete flavor symmetry, the lightest neutral component of Σ is stable and thus can be a dark matter candidate. Its mass can be solely determined by the dark matter relic abundance, which is bout 2.594 TeV. It can still constitute 30% of the dark matter when considering constraints from dark matter indirect detection experiments. The model also predict a dark matter-nucleus scattering cross-section that would be accessible with future dark matter direct detection searches. We further investigate constraints on the parameter space of the model from the lepton-flavor-violating processes and neutrino transition magnetic moments, induced by the Yukawa interaction of the Σ with the left-handed lepton doublets.

Galactic Center gamma ray excess from two Higgs doublet portal dark matter

We consider a simple extension of the type-II two-Higgs-doublet model by introducing a real scalar as a candidate for dark matter in the present Universe. The main annihilation mode of the dark matter particle with a mass of around 31--40 GeV is into a $b\overline{b}$ pair, and this annihilation mode suitably explains the observed excess of the gamma-ray flux from the Galactic Center. We identify the parameter region of the model that can fit the gamma-ray excess and satisfy phenomenological constraints, such as the observed dark matter relic density and the null results of direct dark matter search experiments. Most of the parameter region is found to be within the search reach of future direct dark matter detection experiments.

Simple fermionic dark matter models and Higgs boson couplings

We consider a simple extension of the Standard Model (SM) that incorporates a Majorana fermion dark matter and a charged scalar particle with a coupling to the SM leptons through renormalizable terms. Another renormalizable term involving the charged scalar and the Higgs boson gives rise to interactions between the dark matter and SM quarks at the one-loop level, which induce the elastic scatterings between dark matter and nucleus. The same term also affects the effective coupling of the Higgs boson to diphoton through a one-loop diagram with the charged scalar. Therefore, our model predicts a correlation between the spin-independent cross section for dark matter-nucleus elastic scatterings and a new contribution to the effective Higgs boson coupling to diphoton. When the spin-dependent cross section is large enough to be tested in future direct dark matter detection experiments, the Higgs-diphoton decay rate shows a sizable deviation from the SM prediction. We also consider the case where the fermion dark matter is a Dirac particle. Most of discussions is similar to the Majorana case, but we find that the magnetic dipole moment of the Dirac fermion dark matter is loop-induced and this interaction dominates the spin-independent cross section for dark matter-nucleus elastic scatterings. We find that the resultant cross section is about an order of magnitude below the current experimental bound and hence can be tested in the near future.