Weakly Interacting Massive Particles Mass Research Articles

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.

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.

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.

Charge amplification in low pressure CF4:SF6:He mixtures with a multi-mesh ThGEM for directional dark matter searches

The CYGNO collaboration is developing next generation directional Dark Matter (DM) detection experiments, using gaseous Time Projection Chambers (TPCs), as a robust method for identifying Weakly Interacting Massive Particles (WIMPs) below the Neutrino Fog. SF6 is potentially ideal for this since it provides a high fluorine content, enhancing sensitivity to spin-dependent interactions and, as a Negative Ion Drift (NID) gas, reduces charge diffusion leading to improved positional resolution. CF4, although not a NID gas, has also been identified as a favourable gas target as it provides a scintillation signal which can be used for a complimentary light/charge readout approach. These gases can operate at low pressures to elongate Nuclear Recoil (NR) tracks and facilitate directional measurements. In principle, He could be added to low pressure SF6/CF4 without significant detriment to the length of 16S, 12C, and 19F recoils. This would improve the target mass, sensitivity to lower WIMP masses, and offer the possibility of atmospheric operation; potentially reducing the cost of a containment vessel. In this article, we present gas gain and energy resolution measurements, taken with a Multi-Mesh Thick Gaseous Electron Multiplier (MMThGEM), in low pressure SF6 and CF4:SF6 mixtures following the addition of He. We find that the CF4:SF6:He mixtures tested were able to produce gas gains on the order of 104 up to a total pressure of 100 Torr. These results demonstrate an order of magnitude improvement [1] in charge amplification in NID gas mixtures with a He component.

Charge amplification in sub-atmospheric CF4:He mixtures for directional dark matter searches

Low pressure gaseous Time Projection Chambers (TPCs) are a viable technology for directional Dark Matter (DM) searches and have the potential for exploring the parameter space below the neutrino fog [1,2]. Gases like CF4 are advantageous because they contain flourine which is predicted to have heightened elastic scattering rates with a possible Weakly Interacting Massive Particle (WIMP) DM candidate [3,4,5]. The low pressure of CF4 must be maintained, ideally lower than 100 Torr, in order to elongate potential Nuclear Recoil (NR) tracks which allows for improved directional sensitivity and NR/Electron Recoil (ER) discrimination [6]. Recent evidence suggests that He can be added to heavier gases, like CF4, without significantly affecting the length of 12C and 19F recoils due to its lower mass. Such addition of He has the advantage of improving sensitivity to lower mass WIMPs [1]. Simulations can not reliably predict operational stability in these low pressure gas mixtures and thus must be demonstrated experimentally. In this paper we investigate how the addition of He to low pressure CF4 affects the gas gain and energy resolution achieved with a single Thick Gaseous Electron Multiplier (ThGEM).

MeV to multi-TeV thermal WIMPs: most conservative limits

We consider a weakly interacting massive particle (WIMP) dark matter (DM) annihilating into all possible Standard Model (SM) particle pairs, including the SM neutrinos, via s-wave processes and derive the branching ratio independent upper limit on the total annihilation cross-section 〈σv〉 using the data of CMB, gamma-ray, cosmic-ray and several neutrino observations. For conservative choices of all relevant astrophysical parameters, we obtain upper limits of 10-23–10-25 cm3 s-1 on the total 〈σv〉 for the WIMP mass range 10 MeV–100 TeV, thus making the entire mass range consistent with the observed relic density. An important input that goes into our analysis is the assumption that thermal WIMPs can have significant coupling to the SM neutrinos.

First Dark Matter Search with Nuclear Recoils from the XENONnT Experiment.

We report on the first search for nuclear recoils from dark matter in the form of weakly interacting massive particles (WIMPs) with the XENONnT experiment, which is based on a two-phase time projection chamber with a sensitive liquid xenon mass of 5.9ton. During the (1.09±0.03) ton yr exposure used for this search, the intrinsic ^{85}Kr and ^{222}Rn concentrations in the liquid target are reduced to unprecedentedly low levels, giving an electronic recoil background rate of (15.8±1.3) events/ton yr keV in the region of interest. A blind analysis of nuclear recoil events with energies between 3.3 and 60.5keV finds no significant excess. This leads to a minimum upper limit on the spin-independent WIMP-nucleon cross section of 2.58×10^{-47} cm^{2} for a WIMP mass of 28 GeV/c^{2} at 90% confidence level. Limits for spin-dependent interactions are also provided. Both the limit and the sensitivity for the full range of WIMP masses analyzed here improve on previous results obtained with the XENON1T experiment for the same exposure.

First Dark Matter Search Results from the LUX-ZEPLIN (LZ) Experiment.

The LUX-ZEPLIN experiment is a dark matter detector centered on a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility in Lead, South Dakota, USA. This Letter reports results from LUX-ZEPLIN's first search for weakly interacting massive particles (WIMPs) with an exposure of 60 live days using a fiducial mass of 5.5t. A profile-likelihood ratio analysis shows the data to be consistent with a background-only hypothesis, setting new limits on spin-independent WIMP-nucleon, spin-dependent WIMP-neutron, and spin-dependent WIMP-proton cross sections for WIMP masses above 9 GeV/c^{2}. The most stringent limit is set for spin-independent scattering at 36 GeV/c^{2}, rejecting cross sections above 9.2×10^{-48} cm at the 90% confidence level.

Weakly interacting massive particle cross section limits from LOFAR observations of dwarf spheroidal galaxies

Context. Weakly interacting massive particles (WIMPs) can self-annihilate, thus providing us with a way to indirectly detect dark matter (DM). Dwarf spheroidal (dSph) galaxies are excellent places to search for annihilation signals because they are rich in DM and background emission is low. If O(0.1–10 μG) magnetic fields in dSph galaxies exist, the particles produced in DM annihilation emit synchrotron radiation in the radio band. Aims. We used the non-detection of 150 MHz radio continuum emission from dSph galaxies with the LOw Frequency ARray (LOFAR) to derive constraints on the annihilation cross section of WIMPs in electron–positron pairs. Our main underlying assumption is that the transport of the cosmic rays can be described by the diffusion approximation, which necessitates the existence of magnetic fields. Methods. We used observations of six dSph galaxies in the LOFAR Two-metre Sky Survey (LoTSS). The data were reimaged, and a radial profile was generated for each galaxy. We also used stacking to increase the sensitivity. In order to derive upper limits on the WIMP cross section, we injected fake Gaussian sources into the data, which were then detected with 2σ significance in the radial profile. These sources represent the lowest emission we would have been able to detect. Results. We present limits from the observations of individual galaxies as well as from stacking. We explored the uncertainty due to the choice of diffusion and magnetic field parameters by constructing three different model scenarios: optimistic (OPT), intermediate (INT), and pessimistic (PES). Assuming monochromatic annihilation into electron–positron pairs, the limits from the INT scenario exclude thermal WIMPs (⟨σv⟩≈2.2 × 10−26 cm3 s−1) below 20 GeV, and the limits from the OPT scenario even exclude thermal WIMPs below 70 GeV. The INT limits can compete with limits set by Fermi-LAT using γ-ray observations of multiple dwarf galaxies, and they are especially strong for low WIMP masses.

Search for low-mass dark matter WIMPs with 12 ton-day exposure of DarkSide-50

We report on the search for dark matter weakly interacting massive particles (WIMPs) in the mass range below 10 GeV/c2, from the analysis of the entire dataset acquired with a low-radioactivity argon target by the DarkSide-50 experiment at Laboratori Nazionali del Gran Sasso. The new analysis benefits from more accurate calibration of the detector response, improved background model, and better determination of systematic uncertainties, allowing us to accurately model the background rate and spectra down to 0.06 keVer. A 90% C.L. exclusion limit for the spin-independent cross section of 3 GeV/c2 mass WIMP on nucleons is set at 6×10−43 cm2, about a factor 10 better than the previous DarkSide-50 limit. This analysis extends the exclusion region for spin-independent dark matter interactions below the current experimental constraints in the [1.2, 3.6] GeV/c2 WIMP mass range.5 MoreReceived 28 July 2022Accepted 6 January 2023DOI:https://doi.org/10.1103/PhysRevD.107.063001Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasDark matterParticle dark matterPhysical SystemsWeakly interacting massive particlesTechniquesDark matter detectorsParticle detectorsParticles & FieldsNuclear PhysicsGravitation, Cosmology & Astrophysics

Monoenergetic neutrinos from WIMP annihilation in Jupiter

Weakly interacting massive particles (WIMPs) can be captured by the Sun and annihilate in the core, which may result in production of kaons that can decay at rest into monoenergetic 236 MeV neutrinos. Several studies of detection of these neutrinos at DUNE have been carried out. It has been shown that if the WIMP mass is below 4 GeV, then they will evaporate prior to annihilation, suppressing the signal. Since Jupiter has a cooler core, WIMPs with masses in the 1--4 GeV range will not evaporate and can thus annihilate into kaons which decay at rest into monoenergetic neutrinos. We calculate the flux of these neutrinos near the surface of Jupiter and find that it is comparable to the flux of neutrinos from the Sun at DUNE for masses above 4 GeV and substantially greater in the 1--4 GeV range. Of course, detecting these neutrinos would require a neutrino detector near Jupiter. Obviously, it will be many decades before such a detector can be built, but should direct detection experiments find a WIMP with a mass in the 1--4 GeV range, it may be one of the few ways to learn about the annihilation process. A liquid hydrogen time projection chamber might be able to get precise directional information and energy of these neutrinos (and hydrogen is plentiful in the vicinity of Jupiter). We speculate that such a detector could be placed on the far side of one of the tidally locked Amalthean moons; the moon itself would provide substantial background shielding and the surface would allow easier deployment of solar panels for power generation.

The last complex WIMPs standing

We continue the study of weakly interacting massive particles (WIMP) started in Bottaro et al. (Eur Phys J C 82:31, 2022), focusing on a single complex electroweak n-plet with non-zero hypercharge added to the Standard Model. The minimal splitting between the Dark Matter and its electroweak neutral partner required to circumvent direct detection constraints allows only multiplets with hypercharge smaller or equal to 1. We compute for the first time all the calculable WIMP masses up to the largest multiplet allowed by perturbative unitarity. For the minimal allowed splitting, most of these multiplets can be fully probed at future large-exposure direct detection experiments, with the notable exception of the doublet with hypercharge 1/2. We show how a future muon collider can fully explore the parameter space of the complex doublet combining missing mass, displaced track and long-lived track searches. In the same spirit, we study how a future muon collider can probe the parameter space of complex WIMPs in regions where the direct detection cross section drops below the neutrino floor. Finally, we comment on how precision observables can provide additional constraints on complex WIMPs.

Revisiting constraints on WIMPs around primordial black holes

While primordial black holes (PBHs) with masses ${M}_{\mathrm{PBH}}\ensuremath{\gtrsim}{10}^{\ensuremath{-}11}\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$ cannot comprise the entirety of dark matter, the existence of even a small population of these objects can have profound astrophysical consequences. A subdominant population of PBHs will efficiently accrete dark matter particles before matter-radiation equality, giving rise to high-density dark matter spikes. We consider here the scenario in which dark matter is comprised primarily of weakly interacting massive particles (WIMPs) with a small subdominant contribution coming from PBHs, and revisit the constraints on the annihilation of WIMPs in these spikes using observations of the isotropic gamma-ray background (IGRB) and the cosmic microwave background (CMB), for a range of WIMP masses, annihilation channels, cross sections, and PBH mass functions. We find that the constraints derived using the IGRB have been significantly overestimated (in some cases by many orders of magnitude), and that limits obtained using observations of the CMB are typically stronger than, or comparable to, those coming from the IGRB. Importantly, we show that $\ensuremath{\sim}\mathcal{O}({M}_{\ensuremath{\bigodot}})$ PBHs can still contribute significantly to the dark matter density for sufficiently low WIMP masses and p-wave annihilation cross sections.

Radio bounds on the mixed dark matter scenarios of primordial black holes and WIMPs

We study the synchrotron radio emission in the mixed dark matter scenarios consisting of the primordial black holes (PBHs) and the self-annihilating WIMPs (weakly interacting massive particles). The WIMPs can form the ultracompact minihalos around PBHs and the annihilation enhancement from these dense halos can lead to the efficient synchrotron radiation at the radio frequency in the presence of galactic magnetic fields. The upper bound of PBH fraction with respect to the total dark matter abundance is of order 10-8 ∼ 10-5 depending on the electroweak scale WIMP mass (mχ = 10 ∼ 1000 GeV) and the WIMP annihilation channel (e.g. a hadronic χχ ⟶ bb̅ or a leptonic χχ ⟶ e + e - channel). The PBH contribution to the total dark matter abundance is hence negligible when the other component of dark matter is composed of the conventional electroweak scale WIMPs.

WimPyDD: An object–oriented Python code for the calculation of WIMP direct detection signals

We introduce WimPyDD, a modular, object–oriented and customizable Python code that calculates accurate predictions of nuclear scattering expected rates for Weakly Interacting Massive Particle (WIMP) direct–detection experiments within the framework of Galilean–invariant non–relativistic effective theory in virtually any scenario, including inelastic scattering, an arbitrary WIMP spin and a generic WIMP velocity distribution in the Galactic halo. WimPyDD can also be used to analyze WIMP direct detection signals in halo–independent approaches where the velocity distribution is written in terms of a superposition of streams taken as free parameters. WimPyDD exploits the factorization of the three main components that enter in the calculation of direct detection signals: i) the Wilson coefficients that encode the dependence of the signals on the ultraviolet completion of the effective theory; ii) a response function that depends on the nuclear physics and on the main features of the experimental detector (acceptance, energy resolution, response to nuclear recoils); iii) a halo function that depends on the WIMP velocity distribution and that encodes the astrophysical inputs. In WimPyDD these three components are calculated and stored separately for later interpolation and combined together only as the last step of the signal evaluation procedure. This makes the phenomenological study of the direct detection scattering rate with WimPyDD transparent and fast also when the parameter space of the WIMP model has a large dimensionality. Program summaryProgram Title: WimPyDD (first release: v1.6.1)CPC Library link to program files:https://doi.org/10.17632/rfjb6tkzr8.1Developer's repository link:https://wimpydd.hepforge.orgLicensing provisions: MITProgramming language: Python3Nature of the problem: Weakly Interacting Massive Particles (WIMPs) are the most popular candidates for the Cold Dark Matter that is known to constitute about 25% of the density of the Universe. Direct detection (DD) experiments look for WIMP-nucleus scattering events in solid-state or liquid-state detectors in underground laboratories, and analyze their data only with a limited set of theoretical assumptions. Beyond such assumptions the experimental data need to be re-analyzed on a case-by-case basis. In order to do so accurate signal predictions are needed, which depend on particle physics, nuclear physics and astrophysics inputs, and on the response of each detector. In general scenarios this is usually beyond the capabilities of both model builders and experimentalists. Moreover if the parameter space of the theoretical model is large the calculation of signals becomes cumbersome, because it requires a multiple integration for each choice of the parameters.Solution method: WimPyDD allows to perform accurate DD signal calculations for virtually any scenario, including an arbitrary spin, inelastic scattering, and a non-standard halo function. Each ingredient can be set up independently in an easy and intuitive way. In particular pre-defined nuclear targets, experimental set-ups and effective Hamiltonians are available in the code as objects belonging to dedicated Python classes. Such objects can be directly used, or be adopted as templates to create new ones following the instructions contained in the present paper. More pre-defined objects (such as future experimental set-ups) will be made available on the code website. Moreover, the response of the detector, which represents the most time-consuming part of the calculation, is encoded in tabulated response functions that do not depend on the WIMP mass, on the halo function or the parameters of the effective Hamiltonian and that are interpolated at run time. This allows to explore in a fast and efficient way WIMP theoretical scenarios also when their parameter space is large.

Searching for low-mass dark matter via the Migdal effect in COSINE-100

We report on the search for weakly interacting massive particle (WIMP) dark matter candidates in the galactic halo that interact with sodium and iodine nuclei in the COSINE-100 experiment and produce energetic electrons that accompany recoil nuclei via the the Migdal effect. The WIMP mass sensitivity of previous COSINE-100 searches that relied on the detection of ionization signals produced by target nuclei recoiling from elastic WIMP-nucleus scattering was restricted to WIMP masses above $\sim$5 GeV/$c^2$ by the detectors' 1 keVee energy-electron-equivalent threshold. The search reported here looks for recoil signals enhanced by the Migdal electrons that are ejected during the scattering process. This is particularly effective for the detection of low-mass WIMP scattering from the crystals' sodium nuclei in which a relatively larger fraction of the WIMP's energy is transferred to the nucleus recoil energy and the excitation of its orbital electrons. In this analysis, the low-mass WIMP search window of the COSINE-100 experiment is extended to WIMP mass down to 200 MeV/$c^2$. The low-mass WIMP sensitivity will be further improved by lowering the analysis threshold based on a multivariable analysis technique. We consider the influence of these improvements and recent developments in detector performance to re-evaluate sensitivities for the future COSINE-200 experiment. With a 0.2 keVee analysis threshold and high light-yield NaI(Tl) detectors (22 photoelectrons/keVee), the COSINE-200 experiment can explore low-mass WIMPs down to 20 MeV/$c^2$ and probe previously unexplored regions of parameter space.

Search for dark matter from the centre of the Earth with 8 years of IceCube data

Neutrinos have been proved to be unique messengers in the understanding of fundamental physics processes, and in astrophysical data sets they may provide hints of physics beyond the Standard Model. For example, neutrinos could be the key to discerning between various dark matter models that are based on Weakly Interacting Massive Particles (WIMPs). WIMPs can scatter off standard matter nuclei in the vicinity of massive bodies such as the Sun or the Earth, lose velocity, and be gravitationally trapped in the center of the body. Self-annihilation of dark matter into Standard Model particles may produce an observable flux of neutrinos. For the case of the Earth, an excess of neutrinos coming from the center of the planet could indicate WIMP capture and annihilation at the Earth’s core. The IceCube Neutrino Observatory, located at the geographical South Pole, is sensitive to these excess neutrinos. A search has been conducted on 8 years of IceCube data, probing multiple dark matter channels and masses. With this analysis, we show that IceCube has world-leading sensitivity to the spin-independent dark matter-nucleon scattering cross section above a WIMP mass of 100 GeV.

Indirect search for dark matter in the Galactic Centre with IceCube

Neutrino telescopes such as IceCube can be used to conduct indirect dark matter searches. A common assumption is that dark matter consists of Weakly Interacting Massive Particles (WIMPs), which are expected to produce Standard Model particles when they annihilate or decay. IceCube could then detect the neutrinos generated by these Standard Model particles. Since the Milky Way is expected to be immersed in a dark matter halo whose density increases towards its centre, the Galactic Centre is a designated target for indirect searches. In this contribution, we present the sensitivities of the search for dark matter in the Galactic Centre based on IceCube data, probing annihilation through νeν̅e, νμν̅μ, ντν̅τ, μ+μ-, τ+τ-, W+W- and bb̅. We demonstrate that between WIMP masses of 5 GeV to 1 TeV, the sensitivity of IceCube to the velocity-averaged WIMP self-annihilation cross-section improves by an order of magnitude over previous searches with IceCube and other neutrino telescopes.

The LUX‐ZEPLIN dark matter experiment

AbstractDark matter is one of the greatest mysteries of the Universe. The attributes of the dark matter particles, which make up about 86% of the mass of our Universe, are still obscure. LUX‐ZEPLIN (LZ) will be the most sensitive direct detection dark matter experiment to detect the faint interactions between the dark and ordinary matter. The LZ experiment employs the technology of a dual‐phase xenon time projection chamber (TPC) in combination with a novel active neutron veto to detect Weakly Interacting Massive Particles (WIMPs), one of the propitious dark matter candidates. For a 1,000 live day run, the projected spin‐independent cross‐section sensitivity of LZ is 1.6 × 10−48 cm2 for a 40 GeV c−2 mass WIMP. LZ will also probe the sensitivity to neutrinoless double beta (0νββ) decay of 136Xe. For 1,000 live days, the median exclusion sensitivity to the half‐life of 0νββ decay of 136Xe is predicted to be 1.06 × 1026 years. The LZ experiment is currently under construction and it will start commissioning by the end of 2020.

Review of two-phase emission detectors R&D (Dedicated to the memory of Prof. Boris A. Dolgoshein)

This review is dedicated to the 90th anniversary of the outstanding experimental physicist Boris Anatolyevich Dolgoshein, in whose laboratory exactly 50 years ago the first two-phase emission detector has been created. Today two-phase emission detectors found the best application in the most sensitive at the moment experiments searching for cold dark matter in the form of weakly interacting massive particles (WIMPs). Multi-ton active mass WIMP detectors of the upcoming G3 generation shall become sensitive to solar neutrinos interactions, to double-beta decay of isotopes containing in the working media with naturally occurring isotope abundances. The RED-100 detector constructed at NRNU MEPhI will be used for investigation of the reactor neutrino elastic coherent scattering off xenon nuclei at the Kalinin NPP in 2021. ProtoDUNE-DP prototype emission detector (6x6x6 m3 300 tons LAr) is currently being assembled at the CERN Neutrino Platform in support of the DUNE project focused on investigation of high energy neutrino oscillations. Thus the detector technology invented at MEPhI 50 years has demonstrated a great potential to be used in a variety of fundamental research programs.