DM Mass Research Articles

Transition Edge Sensors with Sub-eV Resolution And Cryogenic Targets (TESSERACT) at the underground laboratory of Modane (LSM)

The future TESSERACT experiment will search for individual galactic DM particles below the proton mass through interactions with advanced, ultra-sensitive detectors. Currently TESSERACT is in a design phase aiming to produce fully defined detector technologies that will explore DM masses down to 10 MeV. It is designed to be sensitive to DM candidates interacting with the detector target material in producing both nuclear recoil DM (NRDM) and electron recoil (ERDM). To do so, multiple target materials will be used with varying detection strategies to ensure the capability to both actively reject the so-called low-energy excess and discriminate nuclear recoils against electron recoils. In addition to maximizing sensitivity to a variety of DM interactions, this provides an independent handle on instrumental backgrounds. Nowadays, the TESSERACT project encompasses two US-based technologies, namely HeRALD using superfluid helium as a target material, and SPICE using polar crystals (Al2O3 and SiO2) and scintillating crystals such as GaAs. In these proceedings, we discuss the recent proposal to host the future TESSERACT experiment at the Modane Underground Laboratory (LSM) and add a third French-based cryogenic semiconducting (Ge, Si) detector technology to the TESSERACT payload.

Directional detection of keV proton and carbon recoils with MIMAC

Directional detection is the dedicated strategy to demonstrate that DM-like signals measured by direct detectors are indeed produced by DM particles from the galactic halo. The experimental challenge of measuring the direction of DM-induced nuclear recoils with (sub-)millimeter tracks has limited, so far, the maximal directional reach to DM masses around 100 GeV. In this paper, we expose the MIMAC detector to three different neutron fields and we develop a method to reconstruct the direction of the neutron-induced nuclear recoils. We measure an angular resolution better than 16° for proton recoils down to a kinetic energy of 4 keV and for carbon recoils down to a kinetic energy of 5.5 keV. For the first time, a detector achieves the directional measurement of proton and carbon recoils with kinetic energies in the keV range without any restriction on the direction of the incoming particle. This work demonstrates that directional detection is around the corner for probing DM with masses down to 𝒪(1 GeV).

Feed restriction of lactating cows triggers acute downregulation of mammary mammalian target of rapamycin signaling and chronic reduction of mammary epithelial mass

While there is generally no consensus about how nutrients determine milk synthesis in the mammary gland, it is likely that the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) plays a role as a key integrator of nutritional and mitogenic signals that can influence a multitude of catabolic and anabolic pathways. The objectives of this study were to evaluate acute changes (<24 h) in translational signaling, in addition to chronic changes (14 d) in mammary gland structure and composition, in response to a severe feed restriction. Fourteen lactating Holstein dairy cows were assigned to either ad libitum feeding (n = 7) or a restricted feeding program (n = 7). Feed-restricted cows had feed removed after the evening milking on d 0. Mammary biopsies and blood samples were collected 16 h after feed removal, after which cows in the restricted group were fed 60% of their previously observed ad libitum intake for the remainder of the study. On d 14, animals were slaughtered and their mammary glands dissected. In response to feed removal, an acute increase in plasma nonesterified fatty acid concentration was observed, concurrent to a decrease in milk yield. In mammary tissue, we observed downregulation of the mTORC1-S6K1 signaling cascade, in addition to reductions in mRNA expression of markers of protein synthesis, endoplasmic reticulum biogenesis, and cell turnover (i.e., transcripts associated with apoptosis or cell proliferation). During the 14 d of restricted feeding, animals underwent homeorhetic adaptation to 40% lower nutrient intake, achieving a new setpoint of 14% reduced milk yield with 18% and 29% smaller mammary secretory tissue DM and CP masses, respectively. On d 14, no treatment differences were observed in markers of protein synthesis or mammary cell turnover evaluated using gene transcripts and immunohistochemical staining. These findings implicate mTORC1-S6K1 in the early phase of the adaptation of the mammary gland's capacity for milk synthesis in response to changes in nutrient supply. Additionally, changes in rates of mammary cell turnover may be transient in nature, returning to basal levels following brief alterations that have sustained effects.

Water masses influence the variation of microbial communities in the Yangtze River Estuary and its adjacent waters.

The Yangtze River estuary (YRE) are strongly influenced by the Kuroshio and terrigenous input from rivers, leading to the formation of distinct water masses, however, there remains a limited understanding of the full extent of this influence. Here the variation of water masses and bacterial communities of 58 seawater samples from the YRE and its adjacent waters were investigated. Our findings suggested that there were 5 water masses in the studied area: Black stream (BS), coastal water in the East China Sea (CW), nearshore mixed water (NM), mixed water in the middle and deep layers of the East China Sea (MM), and deep water blocks in the middle of the East China Sea (DM). The CW mass harbors the highest alpha diversity across all layers, whereas the NM mass exhibits higher diversity in the surface layer but lower in the middle layers. Proteobacteria was the most abundant taxa in all water masses, apart from that, in the surface layer masses, Cyanobacterium, Bacteroidota, and Actinobacteriota were the highest proportion in CW, while Bacteroidota and Actinobacteriota were the highest proportion in NM and BS; in the middle layer, Bacteroidota and Actinobacteriota were dominant phylum in CW and BS masses, but Cyanobacterium was main phylum in NM mass; in the bottom layer, Bacteroidota and Actinobacteriota were the dominant phylum in CW, while Marininimicrobia was the dominated phylum in DM and MM masses. Network analysis suggests water masses have obvious influence on community topological characteristics, moreover, community assembly across masses also differ greatly. Taken together, these results emphasized the significant impact of water masses on the bacterial composition, topological characteristics and assembly process, which may provide a theoretical foundation for predicting alterations in microbial communities within estuarine ecosystems under the influence of water masses.

WIMP constraints from black hole low-mass X-ray binaries

The abnormally fast orbital decay observed in the black hole (BH) Low-Mass X-ray binaries (BH-LMXB) A0620-00 and XTE J1118+480 can be explained by the dynamical friction between Dark Matter (DM) and the companion star orbiting around the low-mass BH (≃ a few M ⊙) of the system. In this case the value of the index γ sp of the DM spike surrounding the BH can be pinned down with an accuracy of ≃ a few percent, way better than that for much bigger systems such as the super massive BHs (SMBHs) in the Galactic Center or in M87. We have used data from XTE J1118+480 to put bounds on the WIMP annihilation cross section times velocity ⟨σv⟩, assuming that DM annihilation is driven by the χχ → bb̅ annihilation channel and that it proceeds in s-wave. The bounds are driven by the radio synchrotron signal produced by e ± final states propagating in the magnetic field in the vicinity of the BH. We find that for DM masses m χ up to the TeV scale XTE J1118+480 allows to constrain ⟨σv⟩ well below the standard value ⟨σv⟩thermal, corresponding to the observed DM relic density in the Universe for a thermal WIMP. On the other hand, for m χ ≳ 15 GeV, the bounds from the SMBHs in the GC or in M87 do not reach ⟨σv⟩thermal when the very large uncertainties on the corresponding spike indices are taken into account, in spite of potentially producing much larger DM densities compared to XTE J1118+480. Our bounds for XTE J1118+480 have a mild sensitivity on the effect of spatial diffusion (which implies at most a weakening of the bounds of a factor ≲ 6 at large m χ). However, diffusion is instrumental in enhancing the sensitivity of the results upon the intensity of the magnetic field. In particular, our bounds rest on the assumption that the magnetic field B reaches the equipartition value B eq. We find that a reduction factor of the magnetic field B eq/B larger than about 14 at low m χ, becoming progressively smaller at higher WIMP masses, would be sufficient to relax the XTE J1118+480 bound to the level of other existing bounds. Recent estimates, albeit not conclusive, may suggest values of B eq/B in BH-LMXB systems as large as 20. This implies that the intensity of the magnetic field in BH-LMXB systems represents the major uncertainty in using them as an alternative to heavier BHs to search for WIMPs.

Musculoskeletal disorders and their associated factors among individuals with diabetes mellitus in northwest Nigeria.

Diabetes mellitus (DM) is a growing public health problem causing a significant amount of disability and mortality in Nigeria. Musculoskeletal disorders (MSDs) are common complications associated with DM. However, studies on the prevalence of MSDs and their associated factors are limited in Nigeria, particularly in the northwest region. The purpose of this study was to determine the prevalence of MSDs and their associated factors among individuals with DM in northwest, Nigeria. A retrospective cross-sectional survey of medical case records of all consecutive patients with DM attending a diabetic clinic in Ahmadu Bello University Teaching Hospital, Zaria was conducted between February 2015 and September 2021. Data on sociodemographic and clinical variables was collected using a researcher-designed questionnaire and analysed using descriptive statistics and logistic regression models. Four hundred eighty-nine cases (170 men [34.8%], 319 females [65.2%]; mean age: 51.4 ±12.3 years) were analysed. The majority of the participants had type 2 DM (96.7%), with a mean DM duration of 7.02 ±5.05 years. The overall prevalence of MSDs was 32.7%, with the highest prevalence found for lumbosacral spondylosis (11%) followed by knee osteoarthritis (8.4%). Among the different potential predictors examined, only duration of DM was significantly associated with overall MSDs (AOR: 1.76, 95% CI: 1.04-2.98; p = 0.035) whereas both duration of DM (AOR: 2.64, 95% CI: 1.19-5.89; p = 0.018) and body mass index (AOR: 7.461, 95% CI: 1.33-43.8; p = 0.023) were significantly associated with lumbosacral spondylosis. Approximately one-third of the study participants had MSDs, with lumbosacral spondylosis being the most frequently occurring disorder. Being obese and having a longer duration of DM were associated with MSDs. Clinicians in Nigeria need to pay attention to MSDs and related factors in DM patients by conducting routine assessments and implementing early treatment.

CASCO: Cosmological and AStrophysical parameters from Cosmological simulations and Observations – I. Constraining physical processes in local star-forming galaxies

ABSTRACT We compare the structural properties and dark matter content of star-forming galaxies taken from the Cosmology and Astrophysics with MachinE Learning Simulations (camels) cosmological simulations to the observed trends derived from the SPARC sample in the stellar mass range $[10^{9}, 10^{11}]\, \textrm {M}_{\odot }$, to provide constraints on the value of cosmological and astrophysical (supernova- and active galactic nucleus-related) parameters. We consider the size–, internal DM fraction–, internal DM mass–, and total–stellar mass relations for all the 1065 simulations, all having different cosmological and astrophysical parameters, from the IllustrisTNG, SIMBA, and ASTRID suites of camels, and search for the parameters that minimize the χ2 with respect to the observations. For the IllustrisTNG suite, we find the following constraints for the cosmological parameters: $\Omega _{\textrm {m}} = 0.27_{-0.05}^{+0.01}$, $\sigma _{8} = 0.83_{-0.11}^{+0.08}$, and $S_{8} = 0.78_{-0.09}^{+0.03}$, which are consistent within 1σ with the results from the 9-yr WMAP observations. SN feedback-related astrophysical parameters, which describe the departure of outflow wind energy per unit star formation rate and wind velocity from the reference IllustrisTNG simulations, assume the following values: $A_{\textrm {SN1}} = 0.48_{-0.16}^{+0.25}$ and $A_{\textrm {SN2}} = 1.21_{-0.34}^{+0.03}$, respectively. Therefore, simulations with a lower value of outflow wind energy per unit star formation rate with respect to the reference illustrisTNG simulation better reproduce the observations. Variation of active galactic nucleus feedback parameters, on the other hand, shows negligible effects on the scaling relation trends in the mass range probed. Simulations based on SIMBA and ASTRID suites predict central dark matter masses substantially larger than those observed in real galaxies, which can be reconciled with observations only by requiring values of Ωm inconsistent with cosmological constraints for SIMBA, or simulations characterized by unrealistic galaxy mass distributions for ASTRID.

Prospects for annihilating dark matter from M31 and M33 observations with the Cherenkov Telescope Array

M31 and M33 are the closest spiral galaxies and the largest members (together with the Milky Way) of the Local group, which makes them interesting targets for indirect dark matter searches. In this paper we present studies of the expected sensitivity of the Cherenkov Telescope Array (CTA) to an annihilation signal from weakly interacting massive particles from M31 and M33. We show that a 100 h long observation campaign will allow CTA to probe annihilation cross-sections up to 〈συ〉 ≈ 5·10-25 cm3 s-1 for the τ + τ - annihilation channel (for M31, at a DM mass of 0.3 TeV), improving the current limits derived by HAWC by up to an order of magnitude. We present an estimate of the expected CTA sensitivity, by also taking into account the contributions of the astrophysical background and other possible sources of systematic uncertainty. We also show that CTA might be able to detect the extended emission from the bulge of M31, detected at lower energies by the Fermi/LAT.

Impact of QCD uncertainties on antiproton spectra from dark-matter annihilation

Dark-matter particles that annihilate or decay can undergo complex sequences of processes, including strong and electromagnetic radiation, hadronisation, and hadron decays, before particles that are stable on astrophysical time scales are produced. Antiprotons produced in this way may leave footprints in experiments such as AMS–02. Several groups have reported an excess of events in the antiproton flux in the rigidity range of 10–20 GV. However, the theoretical modeling of baryon production is not straightforward and relies in part on phenomenological models in Monte Carlo event generators. In this work, we assess the impact of QCD uncertainties on the spectra of antiprotons from dark-matter annihilation. As a proof-of-principle, we show that for a two-parameter model that depends only on the thermally-averaged annihilation cross section (〈σv〉) and the dark-matter mass (Mχ ), QCD uncertainties can affect the best-fit mass by up to ∼ 14% (with large uncertainties for large DM masses), depending on the choice of Mχ and the annihilation channel (bb̅ or W + W -), and 〈σv〉 by up to ∼ 10%. For comparison, changes to the underlying diffusion parameters are found to be within 1%–5%, and the results are also quite resilient to the choice of cosmic-ray propagation model. These findings indicate that QCD uncertainties need to be included in future DM analyses. To facilitate full-fledged analyses, we provide the spectra in tabulated form including QCD uncertainties and code snippets to perform mass interpolations and quick DM fits. The code can be found in this GitHub [1] repository.

Boosting asymmetric charged DM via thermalization

We consider a dark sector scenario with two dark matter species with opposite dark U(1) charges and an asymmetric population comprising some fraction of the dark matter abundance. A new mechanism for boosting dark matter is introduced, arising from the large mass hierarchy between the two particles. In the galaxy, the two species thermalize efficiently through dark Rutherford scattering greatly boosting the lighter dark matter particle, far above the virial and escape velocities in the galaxy, while the dark charge prevents it from escaping. We study the consequences of this scenario for direct-detection experiments, assuming a kinetic mixing between the dark photon and the photon. If the charged dark sector makes up 5% of the total DM mass in our galaxy and the mass ratio is between 103–104, we find that current and future experiments may probe the boosted light dark matter for masses down to 100 keV, in a hitherto unexplored parameter range.

Jump starting the dark sector with a phase transition

We study the possibility to populate the dark sector through a phase transition. We will consider secluded dark sectors made of gauge theories, Randall-Sundrum scenarios and conformally coupled elementary particles. These sectors have in common the fact that the action is approximately Weyl invariant, implying that particle production due to time dependent background is strongly suppressed. In particular no significant production takes place during inflation allowing to avoid strong isocurvature constraints from CMB. As we will show, if the scale of inflation is large compared to the dynamical mass scale, these sectors automatically undergo a phase transition that in the simplest cases is controlled by the Hubble parameter. If the phase transition takes place during reheating or radiation the abundance obtained can be larger than particle production and production from the SM plasma. For phase transitions completing during radiation domination, the DM mass is predicted in the range 108 GeV while larger values are required for phase transitions occurring during reheating.

Detection of inelastic dark matter via electron recoils in SENSEI

The low-threshold experiment SENSEI, which uses the ultralow-noise silicon Skipper-CCD to explore light dark matter from the halo, has achieved the most rigorous limitations on light DM-electron scattering cross section. In this work, we investigate the inelastic DM-electron scattering process with the SENSEI data and derive the constraints on the inelastic dark matter model with a $U(1)$ gauge boson as the mediator. Comparing with elastic scattering process, we find that the down-scattering process with the mass splitting $\delta \equiv m_{\chi_2}-m_{\chi_1}<0$ is more strongly constrained while the up-scattering process $\delta>0$ gets the weaker limits. For the down-scattering process with mass splitting $\delta \sim -5$ eV, the DM mass $m_{\chi}$ can be excluded down to as low as 0.1 MeV.

First dark matter search results from Coherent CAPTAIN-Mills

This paper describes the operation of the Coherent CAPTAIN-Mills (CCM) detector located at the Lujan Neutron Science Center (LANSCE) at Los Alamos National Laboratory (LANL). CCM is a 10-ton liquid argon (LAr) detector located 20 meters from a high flux neutron/neutrino source and is designed to search for sterile neutrinos ($\nu_s$) and light dark matter (LDM). An engineering run was performed in Fall 2019 to study the characteristics of the CCM120 detector by searching for coherent scattering signals consistent with $\nu_s$'s and LDM resulting from $\pi^+$ and $\pi^0$ decays in the tungsten target. New parameter space in a leptophobic dark matter model was excluded for DM masses between $\sim2.0$ and 30 MeV. The lessons learned from this run have guided the development and construction of the new CCM200 detector that will begin operations in 2021 and significantly improve on these searches.

Modular A4 symmetry and light dark matter with gauged U(1)B−L

We propose a radiative seesaw model with a light dark matter candidate (DM) under modular A 4 and gauged U ( 1 ) B − L symmetries, in which neutrino masses are generated via one-loop level, and we have a bosonic DM candidate ∼ 0 . 01 − 50 GeV. In order to forbid the dark matter decays, we have two symmetries; nonzero modular weight and a remnant Z 2 symmetry after spontaneous breaking of U ( 1 ) B − L symmetry. The naturalness of tiny DM mass is indirectly realized by the radiatively induced mass of neutral fermions that interact with our DM candidate. Thus, DM mass does not have to exceed the neutral fermion masses, whose scale is assumed to be 50 GeV. Taking several benchmark points of DM mass in DM analysis, we show the numerical analysis for the neutrino oscillation data in the normal and inverted hierarchy cases and find several features for both cases.

Revisiting the fermionic dark matter absorption on electron target

We perform a systematic study of the fermionic DM absorption interactions on electron target in the context of effective field theory. The fermionic DM absorption is not just sensitive to sub-MeV DM with efficient energy release, but also gives a unique signature with clear peak in the electron recoil spectrum whose shape is largely determined by the atomic effects. Fitting with the Xenon1T and PandaX-II data prefers DM mass at mχ = 59 keV and 105 keV, respectively, while the cut-off scale is probed up to around 1 TeV. The DM overproduction in the early Universe, the invisible decay effect on the cosmological evolution, and the visible decay signal collected by the astrophysical X(gamma)-ray observations (Insight-HXMT, NuSTAR, HEAO-1, and INTEGRAL) are thoroughly explored to constrain the DM absorption interactions. With stringent bounds on the tensor and pseudo-scalar operators, the other fermionic DM operators are of particular interest at tonne-scale direct detection experiments such as PandaX-4T, XENONnT, and LZ.

Electroweak dark matter

In the absence of any hints of new physics in LHC, TeV dark matter candidates interacting through electroweak force (EWDM) are still highly motivated. We extend the Standard Model by adding an arbitrary SU(2) DM multiplet in non-chiral representation. In addition to the well-known real representation which has no coupling to the nuclei at tree level, the complex representation can lead to a new DM candidate providing that one includes a higher dimensional mass-splitting operator, which survives the current direct detection bounds. Since the masses of gauge mediators are light compared to the dark particles, Sommerfeld effect is dominant and affects the value of annihilation cross-section in both the early universe and current time. We computed the relic abundance through freeze-out mechanism in order to determine DM mass. Gamma ray fluxes in our galaxy and dwarf satellites provide a promising tool to probe EWDM theory. We confronted the four fermionic representations of the model with the latest astrophysical observations. It can be concluded that the model passes the current experimental constraints successfully, and it is accessible to future observations.

Dark matter daily modulation with anisotropic organic crystals

Aromatic organic compounds, because of their small excitation energies ~ O(few eV) and scintillating properties, are promising targets for detecting dark matter of mass ~ O(few MeV). Additionally, their planar molecular structures lead to large anisotropies in the electronic wavefunctions, yielding a significant daily modulation in the event rate expected to be observed in crystals of these molecules. We characterize the daily modulation rate of dark matter interacting with an anisotropic scintillating organic crystal such as trans-stilbene, and show that daily modulation is an ~ O(1) fraction of the total rate for small DM masses and comparable to, or larger than, the ~ 10% annual modulation fraction at large DM masses. As we discuss in detail, this modulation provides significant leverage for detecting or excluding dark matter scattering, even in the presence of a non-negligible background rate. Assuming a non-modulating background rate of 1/min/kg that scales with total exposure, we find that a 100 kg yr experiment is sensitive to the cross section corresponding to the correct relic density for dark matter masses between 1.3-14 MeV (1.5-1000 MeV) if dark matter interacts via a heavy (light) mediator. This modulation can be understood using an effective velocity scale v* = Delta E/q*, where Delta E is the electronic transition energy and q* is a characteristic momentum scale of the electronic orbitals. We also characterize promising future directions for development of scintillating organic crystals as dark matter detectors.

Indirect detection constraints on the scotogenic dark matter model

Radiative seesaw models have the attractive property of providing dark matter candidates in addition to the generation of neutrino masses. Here we present a study of neutrino signals from the annihilation of dark matter particles that have been gravitationally captured in the Sun in the framework of the scotogenic model. We compute expected event rates in the IceCube detector in its 86-string configuration. As fermionic dark matter does not scatter off nucleons due to its singlet nature and therefore does not accumulate in the Sun, we study the case of scalar dark matter with a scan over the parameter space. Due to a naturally small mass splitting between the two neutral scalar components, inelastic scattering processes with nucleons can occur. We find that for most of the parameter space, i.e. for mass splittings below 500 keV, inelastic scattering in the Sun yields IceCube event rates above 10 events per year, whereas direct detection on Earth is sensitive only to 250 keV. Consequently, a detailed analysis with IceCube could lead to a lower limit on the scalar coupling λ5≳1.6·10-5· m_ DM/TeV. For larger mass splittings, only elastic scattering occurs in the Sun. In this case, XENON1T limits only allow for models with expected event rates of up to \U0001d4aa(0.1) per year. Some of these models, in particular those with large DM mass and fermion coannihilation, could also be tested with a dedicated IceCube analysis of DM annihilation in the Galactic Center.

Dark matter candidates in a type-II radiative neutrino mass model

We explore the connection between Dark Matter and neutrinos in a model inspired by radiative Type-II seessaw and scotogenic scenarios. In our model, we introduce new electroweakly charged states (scalars and a vector-like fermion) and impose a discrete ℤ2 symmetry. Neutrino masses are generated at the loop level and the lightest ℤ2-odd neutral particle is stable and it can play the role of a Dark Matter candidate. We perform a numerical analysis of the model showing that neutrino masses and flavour structure can be reproduced in addition to the correct dark matter density, with viable DM masses from 700 GeV to 30 TeV. We explore direct and indirect detection signatures and show interesting detection prospects by CTA, Darwin and KM3Net and highlight the complementarity between these observables.

Exploring direct detection suppressed regions in a simple 2-scalar mediator model of scalar dark matter

We explore regions of parameter space that give rise to suppressed direct detection cross sections in a simple model of scalar dark matter with a scalar portal that mixes with the standard model Higgs. We found that even this simple model allows considerable room in the parameter space that has not been excluded by direct detection limits. A number of effects leading to this result have been previously noted. Our main new result explores interference effects between different contributions to DM annihilation when the DM mass is larger than the scalar portal mass. New annihilation channels open up and the parameters of the model need to compensate to give the correct DM relic abundance, resulting in smaller direct detection cross sections. We find that even in a very simple model of DM there are still sizeable regions of parameter space that are not ruled out by experiment.