WIMPs Research Articles

Neutralino dark matter in the extension of MSSM with two triplets and singlet

In an extension of MSSM with two triplets and a singlet, called the TNMSSM, there are seven neutralinos which can enrich the study of cold dark matter if one expects that the weakly interacting massive particle (WIMP) is responsible for the observation of Planck satellite. Such a model, compared to the MSSM, can naturally offer a solution to the μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mu $$\\end{document} problem, and its lightest neutralino, which is bino-like, can also provide a correct relic density by using the coannihilation mechanism due to the newly added triplinos. Taking into account the related experimental measurements, such as the bound on the SM-like Higgs mass, the B meson rare decays, the anomalous magnetic moment of the muon aμ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$a_\\mu $$\\end{document}, the Large Hadron Collider (LHC) measurements and the latest dark matter direct detection experiment LUX-ZEPLIN (LZ), the TNMSSM parameter space can be strictly limited. In respect to all the constraints mentioned above, we find that a bino-like neutralino with a mass in the region [100,450]GeV\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$[100, 450]~\ extrm{GeV}$$\\end{document} can successfully account for the correct dark matter relic density. Additionally, most of the viable parameter space can be tested in the near future experiments such as the Xenon-nT experiment or LHC.

Neutrino roof: Single-scatter cross section ceilings in dark matter direct detection experiments

We identify the maximum cross sections probed by single-scatter weakly interacting massive particle (WIMP) searches in dark matter direct detection. Owing to Poisson fluctuations in scatter multiplicity, these ceilings scale logarithmically with mass for heavy dark matter and often lie in regions probed by multiscatter searches. Using a generalized formula for single-scatter event rates we recast WIMP searches by the quintal-to-tonne scale detectors XENON1T, XENONnT, LZ, PANDAX-II, PANDAX-4T, DarkSide-50, and DEAP-3600 to obtain ceilings and floors up to a few 1017 GeV mass and 10−22 cm2 per nucleus cross section. We do this for coherent, geometric, isospin-violating xenophobic and argophobic spin-independent scattering, and neutron-only and proton-only spin-dependent scattering. Future large-exposure detectors would register an almost irreducible background of atmospheric neutrinos that would determine a dark matter sensitivity ceiling that we call the “neutrino roof,” in analogy with the well-studied “neutrino floor.” Accounting for this background, we estimate the reaches of the 10–100 tonne scale DarkSide-20k, DARWIN/XLZD, PANDAX-xT, and Argo, which would probe many decades of unconstrained parameter space up to the Planck mass, as well as of 103–104 tonne scale noble liquid detectors that have been proposed in synergy with neutrino experiments. Published by the American Physical Society 2024

Dark sector tunneling field potentials for a dark big bang

All of the significant evidence for dark matter observed thus far has been through its gravitational interactions. After 40 years of direct detection experiments, the parameter space for weakly interacting massive particles (WIMPs) as dark matter candidates is rapidly approaching the neutrino floor. Moreover, there have been no signs of WIMPs in any particle production experiments so far. In this light, we consider a dark sector that is strongly decoupled from the visible sector, interacting exclusively through gravity. In this model, proposed by Freese and Winkler [Dark matter and gravitational waves from a dark big bang, ], dark matter can be produced through a first-order phase transition in the dark sector dubbed “the dark big bang.” We fully determine the allowed region of parameter space for the tunneling potential that leads to the realization of a dark big bang and is consistent with all experimental bounds available. Published by the American Physical Society 2024

Dark matter limits from the tip of the red giant branch of globular clusters

Capture and annihilation of weakly interacting massive particle (WIMP)-like dark matter in red giant stars can lead to faster-than-expected ignition of the helium core, and thus a lower tip of the red giant branch (TRGB) luminosity. We use data to place constraints on the dark matter-nucleon cross section using 22 globular clusters with measured TRGB luminosities, and place projections on the sensitivity resulting from 161 clusters with full phase space distributions observed by . Although limits remain weaker than those from Earth-based direct detection experiments, they represent a constraint that is fully independent of dark matter properties in the solar neighborhood, probing its properties across the entire Milky Way galaxy. Based on our findings, it is likely that the use of the TRGB as a standard candle in H0 measurements is very robust against the effects of dark matter. Published by the American Physical Society 2024

Enhancing the light yield of He:CF4 based gaseous detector

The CYGNO experiment aims to build a large (O(10) m3) directional detector for rare event searches, such as nuclear recoils (NRs) induced by dark matter (DM), such as weakly interactive massive particles (WIMPs). The detector concept comprises a time projection chamber (TPC), filled with a He:CF4 60/40 scintillating gas mixture at room temperature and atmospheric pressure, equipped with an amplification stage made of a stack of three gas electron multipliers (GEMs) which are coupled to an optical readout. The latter consists in scientific CMOS (sCMOS) cameras and photomultipliers tubes (PMTs). The maximisation of the light yield of the amplification stage plays a major role in the determination of the energy threshold of the experiment. In this paper, we simulate the effect of the addition of a strong electric field below the last GEM plane on the GEM field structure and we experimentally test it by means of a 10 × 10 cm2 readout area prototype. The experimental measurements analyse stacks of different GEMs and helium concentrations in the gas mixture combined with this extra electric field, studying their performances in terms of light yield, energy resolution and intrinsic diffusion. It is found that the use of this additional electric field permits large light yield increases without degrading intrinsic characteristics of the amplification stage with respect to the regular use of GEMs.

ANAIS–112 three years data: a sensitive model independent negative test of the DAMA/LIBRA dark matter signal

Weakly interacting massive particles (WIMPs) are well-motivated candidates for dark matter. One signature of galactic WIMPs is the annual modulation expected in a detector’s interaction rate, which arises from Earth’s revolution around the Sun. Over two decades, the DAMA/LIBRA experiment has observed such modulation with 250 kg of NaI(Tl) scintillators, in accordance with WIMP expectations but inconsistent with the negative results of other experiments. The signal depends on the target material, so to validate or refute the DAMA result, the experiment must be replicated using the same material. This is the goal of the ANAIS–112 experiment, currently underway since August 2017 with 112.5 kg of NaI(Tl). In this work, we present a reanalysis of three years of data employing an improved analysis chain to enhance the experimental sensitivity. The results presented here are consistent with the absence of modulation and inconsistent with DAMA’s observation at nearly 3σ confidence level, with the potential to reach a 5σ level within 8 years from the beginning of the data collection. Additionally, we explore the impact of different scintillation quenching factors in the comparison between ANAIS–112 and DAMA/LIBRA.

Heavy neutrino as dark matter in a neutrinophilic U(1) model

We study the prospect of heavy singlet neutrinos as a dark matter (DM) candidate within a neutrinophilic U(1) model, where the Standard Model (SM) is extended with a U(1) gauge symmetry, and neutrino mass and oscillation parameters are explained through an inverse see-saw mechanism. The lightest of the heavy neutrinos plays the role of the DM, while the newly introduced scalars and the extra gauge boson Z′\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Z'$$\\end{document} act as mediators between the dark sector and the SM sector. We show the range of model parameters where this DM candidate can be accommodated in the Weakly Interacting Massive Particle (WIMP) or Feebly Interacting Massive Particle (FIMP) scenario. The observed DM relic density (DMRD) is achieved via the new gauge boson and singlet scalar portals in the WIMP scenario, whereas within the FIMP scenario, these two particles assume a distinct yet pivotal role in generating the observed DMRD.

Singlet–doublet Dirac Fermion dark matter from Peccei–Quinn symmetry

Weakly interacting massive particles (WIMPs) and axions are arguably the most compelling dark matter (DM) candidates in the literature. Here, we consider a model where the Peccei–Quinn (PQ) symmetry solves the strong CP problem, generates radiatively Dirac neutrino masses and gives origin to a multicomponent dark sector. Specifically, scotogenic Dirac neutrino masses arise at one-loop level. The lightest fermionic mediator acts as the second DM candidate due to a residual [Formula: see text] symmetry resulting from the PQ symmetry breaking. The WIMP DM component resembles the well-known singlet–doublet fermion DM. While the lower WIMP dark mass region is usually excluded, our model reopens that portion of the parameter space (for DM masses below [Formula: see text][Formula: see text]GeV). Therefore, we perform a phenomenological analysis that addresses the constraints from direct searches of DM, neutrino oscillation data and charged lepton flavor violating processes. The model can be tested in future facilities where neutrino telescopes search for DM annihilation into Standard Model particles.

Unveiling desert region in inert doublet model assisted by Peccei-Quinn symmetry

The Inert Higgs Doublet model (IDM), assisted by Peccei-Quinn (PQ) symmetry, offers a simple but natural framework of a dark sector that accommodates Weakly Interacting Massive Particle (WIMP) and axion as dark matter components. Spontaneous breaking of U(1)PQ symmetry, which was originally proposed as an elegant solution to the strong charge-parity (CP) problem, also ensures the stability of WIMP through a residual ℤ2 symmetry. Interestingly, additional fields necessitated by PQ symmetry further enrich the dark sector. These include a scalar field proprietor for axion DM and a vector-like quark (VLQ) that acts as a portal for the dark sector through Yukawa interactions. Moreover, this combination of the axion and WIMP components satisfies the observed DM relic density and reopens the phenomenologically exciting region of the IDM parameter space where the WIMP mass falls between 100 - 550 GeV. We investigate the model-independent pair production of VLQs exploring this region at the Large Hadron Collider (LHC), incorporating the effects of next-to-leading order (NLO) QCD corrections. After production, each VLQ decays into a top or bottom quark accompanied by an inert scalar, a consequence of the residual ℤ2 symmetry. Utilising relevant observables with a leptonic search channel and employing multivariate analysis, we demonstrate the ability of this analysis to exclude a significant portion of the parameter space with an integrated luminosity of 300 fb−1.

Theoretical WIMP–Nucleus Scattering Rates for Isomeric Nuclei

The direct detection of dark matter constituents, particularly weakly interacting massive particles (WIMPs), is central to particle physics and cosmology. In this paper, we develop the formalism for WIMP–nucleus-induced transitions from isomeric nuclear states, with particular focus on the experimentally interesting target 180Ta.

Dark matter scattering off H2 and He4 nuclei within chiral effective field theory

We study dark matter, assumed to be composed of weak interacting massive particles (WIMPs), scattering off H2 and He4 nuclei. In order to parametrize the WIMP-nucleon interaction, the chiral effective field theory approach is used. Considering only interactions invariant under parity, charge conjugation, and time reversal, we examine five interaction types: scalar, pseudoscalar, vector, axial, and tensor. Scattering amplitudes between two nucleons and a WIMP are determined up to second order of chiral perturbation theory. We apply this program to calculate the interaction rate as a function of the WIMP mass and of the magnitude of the WIMP-quark coupling constants. From our study, we conclude that the scalar nuclear response functions is much greater than the others due to their large combination of low energy constants. We verify that the leading order contributions are dominant in these low energy processes. We also provide an estimate for the background due to atmospheric neutrinos. Published by the American Physical Society 2024

Gamma rays from dark matter spikes in EAGLE simulations

Intermediate Mass Black Holes (IMBHs) with a mass range between 100 M⊙ and 106 M⊙ are expected to be surrounded by high dark matter densities, so-called dark matter spikes.The high density of self-annihilating Weakly Interacting Massive Particles (WIMPs) in these spikes leads to copious gamma-ray production. Sufficiently nearby IMBHs could therefore appear as unidentified gamma-ray sources.However, the number of IMBHs and their distribution within our own Milky Way is currently unknown. In this work, we provide a mock catalogue of IMBHs and their dark matter spikes obtained from the EAGLE simulations, in which black holes with a mass of 105 M⊙/h are seeded into the centre of halos greater than 1010 M⊙/h to model black hole feedback influencing the formation of galaxies.The catalogue contains the coordinates and dark matter spike parameters for about 2500 IMBHs present in about 150 Milky Way-like galaxies. We expect about 15+9 -6 IMBHs within our own galaxy, mainly distributed in the Galactic Centre and the Galactic Plane. In the most optimistic scenario, we find that current and future gamma-ray observatories, such as Fermi-LAT, H.E.S.S. and CTAO, would be sensitive enough to probe the cross section of dark matter self-annihilation around IMBHs down to many orders of magnitude below the thermal relic cross section for dark matter particles with masses from GeV to TeV.We have made the IMBH mock catalogue and the source code for our analysis publicly available, providing the resources to study dark matter self-annihilation around IMBHs with current and upcoming gamma-ray observatories.

Probing the scalar WIMP-pion coupling with the first LUX-ZEPLIN data

Weakly interacting massive particles (WIMPs) may interact with a virtual pion that is exchanged between nucleons. This interaction channel is important to consider in models where the spin-independent isoscalar channel is suppressed. Using data from the first science run of the LUX-ZEPLIN dark matter experiment, containing 60 live days of data in a 5.5 tonne fiducial mass of liquid xenon, we report the results on a search for WIMP-pion interactions. We observe no significant excess and set an upper limit of 1.5 × 10−46 cm2 at a 90% confidence level for a WIMP mass of 33 GeV/c2 for this interaction.

The design, implementation, and performance of the LZ calibration systems

LUX-ZEPLIN (LZ) is a tonne-scale experiment searching for direct dark matter interactions and other rare events. It is located at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. The core of the LZ detector is a dual-phase xenon time projection chamber (TPC), designed with the primary goal of detecting Weakly Interacting Massive Particles (WIMPs) via their induced low energy nuclear recoils. Surrounding the TPC, two veto detectors immersed in an ultra-pure water tank enable reducing background events to enhance the discovery potential. Intricate calibration systems are purposely designed to precisely understand the responses of these three detector volumes to various types of particle interactions and to demonstrate LZ's ability to discriminate between signals and backgrounds. In this paper, we present a comprehensive discussion of the key features, requirements, and performance of the LZ calibration systems, which play a crucial role in enabling LZ's WIMP-search and its broad science program. The thorough description of these calibration systems, with an emphasis on their novel aspects, is valuable for future calibration efforts in direct dark matter and other rare-event search experiments.

Dark matter and its candidate particles

Theoretically predicted unseen matter called dark matter may be present in the universe. Even though it might be the primary component of cosmic matter, it is not a part of any known material that makes up a visible celestial body. Despite the fact that dark matter has not yet been directly observed, there is a wealth of evidence to support its existence, for example, through the autobiographical curve of the Milky Way, the mass distribution of galaxy clusters, the background radiation of the universe microwaves, and the formation of large-scale structures of the universe. Although great progress has been made in cosmic observation, we are still unable to determine what the constituent particles of dark matter are.There are the following speculations about what particles dark matter is composed of: baryon dark matter, such as MACHOs, rogue planets, and other possibilities; Non-baryonic dark matter: Weakly Interacting Massive Particles (WIMPs); Axion; Neutrino, etc.

Measurement of the sodium and iodine scintillation quenching factors across multiple NaI(Tl) detectors to identify systematics

The amount of light produced by nuclear recoils in scintillating targets is strongly quenched compared to that produced by electrons. A precise understanding of the quenching factor is particularly interesting for weakly interacting massive particles (WIMP) searches and coherent elastic neutrino-nucleus scattering (CEνNS) measurements since both rely on nuclear recoils, whereas energy calibrations are more readily accessible from electron recoils. There is a wide variation among the current measurements of the quenching factor in sodium iodide (NaI) crystals, especially below 10 keV, the energy region of interest for dark matter and CEνNS studies. A better understanding of the quenching factor in NaI(Tl) is of particular interest for resolving the decades-old puzzle in the field of dark matter between the null results of most WIMP searches and the claim for dark matter detection by the DAMA/LIBRA collaboration. In this work, we measured sodium and iodine quenching factors for five small NaI(Tl) crystals grown with similar thallium concentrations and growth procedures. Unlike previous experiments, multiple crystals were tested, with measurements made in the same experimental setup to control systematic effects. The quenching factors agree in all crystals we investigated, and both sodium and iodine quenching factors are smaller than those reported by DAMA/LIBRA. The dominant systematic effect was due to the electron equivalent energy calibration originating from the nonproportional behavior of the NaI(Tl) light yield at lower energies, potentially the cause for the discrepancies among the previous measurements. Published by the American Physical Society 2024

Projected WIMP sensitivity of the CDEX-50 dark matter experiment

CDEX-50 is a next-generation project of the China Dark Matter Experiment (CDEX) that aims to search for dark matter using a 50-kg germanium detector array. This paper comprises a thorough summary of the CDEX-50 dark matter experiment, including an investigation of potential background sources and the development of a background model. Based on the baseline model, the projected sensitivity of weakly interacting massive particle (WIMP) is also presented. The expected background level within the energy region of interest, set to 2–2.5 keVee, is ∼0.01 counts keVee-1 kg-1 day-1. At 90% confidence level, the expected sensitivity to spin-independent WIMP-nucleon couplings is estimated to reach a cross-section of 5.1 × 10-45 cm2 for a WIMP mass of 5 GeV/c2 with an exposure objective of 150 kg·year and an analysis threshold of 160 eVee. This science goal will correspond to the most sensitive results for WIMPs with a mass of 2.2–8 GeV/c2.

Investigation of scintillation properties of a CsI(Tl) crystal at low temperature for dark matter search

The Korea invisible mass search (KIMS) experiment used CsI(Tl) crystals coupled with photomultiplier tubes (PMTs) to detect signals from weakly interacting massive particles (WIMPs) at room temperature. It is expected that combining CsI(Tl) crystals with silicon photomultipliers (SiPMs) will enhance the detection performance. However, SiPMs must operate at low temperatures to reduce the dark count rate. In this study, we examined the temperature dependence of CsI(Tl) crystal properties, including light yield, α/β ratio, decay time, and pulse shape discrimination, before integrating it with a SiPM. The CsI(Tl) crystal was placed in a low-temperature chamber with a radiation source, and scintillation photons were detected by a PMT positioned outside the chamber. The response of CsI(Tl) to α-particles and γ-rays was examined across temperatures ranging from 10 K to 300 K.

Direct WIMP detection rates for transitions in isomeric nuclei

The direct detection of dark matter constituents, in particular the weakly interacting massive particles (WIMPs), is central to particle physics and cosmology. In this paper we study WIMP induced transitions from isomeric nuclear states for two possible isomeric candidates: Ta180 and Ho166. The experimental setup, which can measure the possible decay of Ta180 induced by WIMPs, was proposed. The corresponding estimates of the half-life of Ta180 are given in the sense that the WIMP-nucleon interaction can be interpreted as ordinary radioactive decay.

Analysis of the Composition and Characteristics of Dark Matter

Today, astronomers use different methods to study the structure and evolution of the universe. However, they will all be affected by other factors such as light or electromagnetic radiation. It is impossible to accurately observe the structure of the universe in the distant past. To find objects that fit the criteria, the existence of dark matter was assumed. It only has a gravitational effect and will be less affected. The composition and characteristics of dark matter are important research foundations. In this paper, the Cosmic Microwave Background (CMB) and power spectrum are used to study the status of dark matter in the universe. The search found Weakly Interacting Massive Particles (WIMPs) to be a candidate in the dark matter component. The three types of dark matter are cold dark matter, warm dark matter, and hot dark matter. Comparing their respective characteristics, it is concluded that cold dark matter (CDM) is the condition for observing large-scale structures. The result is that dark matter constitutes the second largest component of the universe. WIMPs are more suitable candidates than Neutrinos. CDM is best suited for studying large-scale structures over time. Eventually, it will be discovered that dark matter has strong stability, which will help astronomers find the process of universe evolution. Dark matter is also an important player that is best used to study the structure and evolution of the universe.