Found 1435 results, showing the newest relevant preprints. Sort by relevancy only.Update me on new preprints

Projected sensitivity to sub-GeV **dark** **matter** of next-generation
semiconductor detectors

We compute the projected sensitivity to dark matter (DM) particles in the sub-GeV mass range of future direct detection experiments using germanium and silicon semiconductor targets. Expand abstract.

We compute the projected sensitivity to

**dark****matter**(DM) particles in the sub-GeV mass range of future direct detection experiments using germanium and silicon semiconductor targets. We perform this calculation within the**dark**photon model for DM-electron interactions using the likelihood ratio as a test statistic, Monte Carlo simulations, and background models that we extract from recent experimental data. We present our results in terms of DM-electron scattering cross section values required to reject the background only hypothesis in favour of the background plus DM signal hypothesis with a statistical significance, $\mathcal{Z}$, corresponding to 3 or 5 standard deviations. We also test the stability of our conclusions under changes in the astrophysical parameters governing the local space and velocity distribution of DM in the Milky Way. In the best-case scenario, when a high-voltage germanium detector with an exposure of $50$ kg-year and a CCD silicon detector with an exposure of $1$ kg-year and a**dark**current rate of $1\times10^{-7}$ counts/pixel/day have simultaneously reported a DM signal, we find that the smallest cross section value compatible with $\mathcal{Z}=3$ ($\mathcal{Z}=5$) is about $8\times10^{-42}$ cm$^2$ ($1\times10^{-41}$ cm$^2$) for contact interactions, and $4\times10^{-41}$ cm$^2$ ($7\times10^{-41}$ cm$^2$) for long-range interactions. Our sensitivity study extends and refine previous works in terms of background models, statistical methods, and treatment of the underlying astrophysical uncertainties.3 days ago

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arXiv

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arXiv

Heating neutron stars with GeV **dark** **matter**

An old neutron star (NS) may capture halo

**dark****matter**(DM) and get heated up by the deposited kinetic energy, thus behaving like a thermal DM detector with sensitivity to a wide range of DM masses and a variety of DM-quark interactions. Expand abstract. An old neutron star (NS) may capture halo

**dark****matter**(DM) and get heated up by the deposited kinetic energy, thus behaving like a thermal DM detector with sensitivity to a wide range of DM masses and a variety of DM-quark interactions. Near future infrared telescopes will measure NS temperatures down to a few thousand Kelvin and probe NS heating by DM capture. We focus on GeV-mass Dirac fermion DM (which is beyond the reach of current DM direct detection experiments) in scenarios in which the DM capture rate can saturate the geometric limit. For concreteness, we study (1) a model that invokes**dark**decays of the neutron to explain the neutron lifetime anomaly, and (2) a framework of DM coupled to quarks through a vector current portal. In the neutron**dark**decay model a NS can have a substantial DM population, so that the DM capture rate can reach the geometric limit through DM self-interactions even if the DM-neutron scattering cross section is tiny. We find NS heating to have greater sensitivity than multi-pion signatures in large underground detectors for the neutron**dark**decay model, and sub-GeV gamma-ray signatures for the quark vector portal model.3 days ago

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arXiv

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arXiv

Signatures of Velocity-Dependent **Dark** **Matter** Self-Interactions in Milky
Way-mass Halos

We explore the impact of elastic, anisotropic, velocity-dependent dark matter (DM) self-interactions on the host halo and subhalos of Milky Way (MW)-mass systems. Expand abstract.

We explore the impact of elastic, anisotropic, velocity-dependent

**dark****matter**(DM) self-interactions on the host halo and subhalos of Milky Way (MW)-mass systems. We consider a generic self-interacting**dark****matter**(SIDM) model parameterized by the masses of a light mediator and the DM particle. The ratio of these masses, $w$, sets the velocity scale above which momentum transfer due to DM self-interactions becomes inefficient. We perform high-resolution zoom-in simulations of a MW-mass halo for values of $w$ that span scenarios in which self-interactions between either the host and its subhalos, or only within subhalos, efficiently transfer momentum, and we study the effects of self-interactions on the host halo and on the abundance, radial distribution, orbital dynamics, and density profiles of subhalos in each case. The abundance and properties of surviving subhalos are consistent with being determined primarily by subhalo--host halo interactions. In particular, subhalos on radial orbits in models with larger values of the cross section at the host halo velocity scale are more susceptible to tidal disruption due to mass loss from ram-pressure stripping caused by self-interactions with the host. This mechanism suppresses the abundance of surviving subhalos relative to collisionless DM simulations, with stronger suppression for larger values of $w$. Thus, probes of subhalo abundance around MW-mass hosts can be used to place upper limits on the self-interaction cross section at velocity scales of $\sim 200\ \rm{km\ s}^{-1}$, and combining these measurements with the inferred orbital properties and internal dynamics of subhalos may break degeneracies among velocity-dependent SIDM models.4 days ago

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arXiv

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arXiv

Proton Decay and Axion **Dark** **Matter** in SO(10) Grand Unification via
Minimal Left-Right Symmetry

We study the proton lifetime in the $SO(10)$ Grand Unified Theory (GUT), which has the left-right (LR) symmetric gauge theory below the GUT scale. Expand abstract.

We study the proton lifetime in the $SO(10)$ Grand Unified Theory (GUT), which has the left-right (LR) symmetric gauge theory below the GUT scale. In particular, we focus on the minimal model without the bi-doublet Higgs field in the LR symmetric model, which predicts the LR-breaking scale at around $10^{10\text{--}12}$ GeV. The Wilson coefficients of the proton decay operators turn out to be considerably larger than those in the minimal $SU(5)$ GUT model especially when the Standard Model Yukawa interactions are generated by integrating out extra vector-like multiplets. As a result, we find that the proton lifetime can be within the reach of the Hyper-Kamiokande experiment even when the GUT gauge boson mass is in the $10^{16\text{--}17}$ GeV range. We also show that the mass of the extra vector-like multiplets can be generated by the Peccei-Quinn symmetry breaking in a consistent way with the axion

**dark****matter**scenario.12 days ago

10/10 relevant

arXiv

10/10 relevant

arXiv

QED2 boson description of the X17 particle and **dark** **matter**

The oscillations of the color charges and electric charges of the quark and antiquarks of the underlying vacuum in a flux tube generate QCD2 bosons (mesons) and QED2 bosons (Phys. Expand abstract.

The oscillations of the color charges and electric charges of the quark and antiquarks of the underlying vacuum in a flux tube generate QCD2 bosons (mesons) and QED2 bosons (Phys.Rev.C81,064903(2010)). The predicted mass of the isoscalar QED2 boson in the flux tube environment is close to the X17 mass, leading to the suggestion that the X17 particle may be the isoscalar $I(J^\pi)$=0(0$^-$) QED2 boson arising from the oscillation of the electric charges of the quarks and antiquarks of the vacuum in the flux tube that mediates the meson-exchange interaction between the nucleon and the nuclear core in the excited 0(0$^-$) state of $^4$He. The isoscalar 0(0$^-$) QED2 boson can decay into an electron-positron pair or two photons in free space but the decays will be inhibited if the gravitational binding energy of the QED2 boson bound in a QED2 boson assembly exceeds its rest mass. Consequently, a self-gravitating isoscalar QED2 boson assembly whose mass $M$ and radius $R$ satisfy $(M/M_\odot)/(R/R_\odot) \gtrsim 4.71 \times 10^5$ will not produce electron-positron pairs or photons and may be a good candidate for a primordial

**dark****matter**.13 days ago

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arXiv

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arXiv

Scale-Invariant Dynamics of Galaxies, MOND, **Dark** **Matter**, and the Dwarf
Spheroidals

The Scale-Invariant Vacuum (SIV) theory is based on Weyl's Integrable Geometry, endowed with a gauge scalar field. Expand abstract.

The Scale-Invariant Vacuum (SIV) theory is based on Weyl's Integrable Geometry, endowed with a gauge scalar field. The main difference between MOND and the SIV theory is that the first considers a global dilatation invariance of space and time, where the scale factor $\lambda$ is a constant, while the second opens the likely possibility that $\lambda$ is a function of time. The key equations of the SIV framework are used here to study the relationship between the Newtonian gravitational acceleration due to baryonic

**matter**$g_{\mathrm{bar}}$ and the observed kinematical acceleration $g_{\mathrm{obs}}$. The relationship is applied to galactic systems of the same age where the Radial Acceleration Relation (RAR), between the $g_{\mathrm{obs}}$ and $g_{\mathrm{bar}}$ accelerations, can be compared with observational data. The SIV theory shows an excellent agreement with observations and with MOND for baryonic gravities $g_{\mathrm{bar}}>10^{-11.5}$ m s$^{-2}$. Below this value, SIV still fully agrees with the observations, as well as with the horizontal asymptote of the RAR for dwarf spheroidals, while this is not the case for MOND. These results support the view that there is no need for**dark****matter**and that the RAR and related dynamical properties of galaxies can be interpreted by a modification of gravitation.13 days ago

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arXiv

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arXiv

Axion **Dark** **Matter** Search around 6.7 $\mu$eV

An axion dark matter search with the CAPP-8TB haloscope is reported. Expand abstract.

An axion

**dark****matter**search with the CAPP-8TB haloscope is reported. Our results are sensitive to axion-photon coupling $g_{a\gamma\gamma}$ down to the QCD axion band over the axion mass range between 6.62 and 6.82 $\mu$eV at a 90\% confidence level, which is the most sensitive result in the mass range to date.13 days ago

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arXiv

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arXiv

Constraints to **dark** **matter** annihilation from high-latitude HAWC
unidentified sources

The $\Lambda$CDM cosmological framework predicts the existence of thousands of subhalos in our own Galaxy not massive enough to retain baryons and become visible. Expand abstract.

The $\Lambda$CDM cosmological framework predicts the existence of thousands of subhalos in our own Galaxy not massive enough to retain baryons and become visible. Yet, some of them may shine in gamma rays provided that the

**dark****matter**(DM) is made of weakly interacting massive particles (WIMPs), that would self-annihilate and would appear as unidentified gamma-ray sources (unIDs) in gamma-ray catalogs. Indeed, unIDs have proven to be competitive targets for DM searches with gamma rays. In this work, we focus on the three high-latitude ($|b|\geq 10^\circ$) sources present in the 2HWC catalog of the High Altitude Water Cherenkov (HAWC) observatory with no associations at other wavelenghts. Indeed, only one of these sources, 2HWC J1040+308, is found to be above the HAWC detection threshold when considering 760 days of data, a factor 1.5 more exposure time than in the original 2HWC catalog. Other instruments such as Fermi-LAT or VERITAS at lower energies do not detect this source. Also, this unID is reported as spatially extended, making it even more interesting in a DM search context. While waiting for more data that may shed further light on the nature of this source, we set competitive upper limits on the annihilation cross section by comparing this HAWC unID to expectations based on state-of-the-art N-body cosmological simulations of the Galactic subhalo population. We find these constraints to be particularly competitive for heavy WIMPs, i.e., masses above $\sim 25$ (40) TeV in the case of the $b\bar{b}$ ($\tau^+\tau^-$) annihilation channel, reaching velocity-averaged cross section values of $2\cdot10^{-25}$ ($5\cdot10^{-25}$) $cm^3s^{-1}$. Although far from the thermal relic cross section value, the obtained limits are independent and nicely complementary to those from radically different DM analyses and targets, demonstrating again the high potential of this DM search approach.19 days ago

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arXiv

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arXiv

The stellar-to-halo mass relation over the past 12 Gyr

We use a statistical approach to link the observed galaxy stellar mass functions on the COSMOS field to

**dark****matter**halo mass functions from the DUSTGRAIN simulation and from a theoretical parametrization from z=0 to z=4. Expand abstract. Understanding how galaxy properties are linked to the

**dark****matter**halos they reside in, and how they co-evolve is a powerful tool to constrain the processes related to galaxy formation. The stellar-to-halo mass relation (SHMR) and its evolution over the history of the Universe provides insights on galaxy formation models and allows to assign galaxy masses to halos in N-body**dark****matter**simulations. We use a statistical approach to link the observed galaxy stellar mass functions on the COSMOS field to**dark****matter**halo mass functions from the DUSTGRAIN simulation and from a theoretical parametrization from z=0 to z=4. We also propose an empirical model to describe the evolution of the stellar-to-halo mass relation as a function of redshift. We calculate the star-formation efficiency (SFE) of galaxies and compare results with previous works and semi-analytical models.20 days ago

5/10 relevant

arXiv

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arXiv

Interacting R'enyi holographic **dark** energy with parametrization on the
interaction term

In the present work, we study the R$\acute{e}$nyi holographic dark energy model (RHDE) in a flat FRW Universe where the infrared cut-off is taken care by the Hubble horizon and also by taking three different parametrizations of the interaction term between the dark matter and the dark energy. Expand abstract.

In the present work, we study the R$\acute{e}$nyi holographic

**dark**energy model (RHDE) in a flat FRW Universe where the infrared cut-off is taken care by the Hubble horizon and also by taking three different parametrizations of the interaction term between the**dark****matter**and the**dark**energy. Analysing graphically, the behaviour of some cosmological parameters in particular deceleration parameter, squared speed of sound and equation of state (EoS) parameter, in the process of the cosmic evolution, is found to be leading towards the late-time accelerated expansion of RHDE model.20 days ago

4/10 relevant

arXiv

4/10 relevant

arXiv