Found 1083 results, showing the newest relevant preprints. Sort by relevancy only.Update me on new preprints

SUSY-QCD corrected and Sommerfeld enhanced stau annihilation into heavy quarks with scheme and scale uncertainties

We investigate stau-antistau annihilation into heavy quarks in the phenomenological Minimal Supersymmetric Standard Model within the \DMNLO project. Expand abstract.

We investigate stau-antistau annihilation into heavy quarks in the phenomenological Minimal Supersymmetric Standard Model within the \DMNLO project. We present the calculation of the corresponding cross section including corrections up to $\mathcal{O}(\alpha_s)$ and QED Sommerfeld enhancement. The numerical impact of these corrections is discussed for the cross section and the

**dark****matter**relic density, where we focus on top-quark final states and consider either neutralino or gravitino**dark****matter**. Similarly to previous work, we find that the presented corrections should be included when calculating the relic density or extracting parameters from cosmological observations. Considering scheme and scale variations, we estimate the theoretical uncertainty that affects the prediction of the annihilation cross section and thus the prediction of the relic density.3 days ago

4/10 relevant

arXiv

4/10 relevant

arXiv

**Dark** **Matter** Mass and Anisotropy in Directional Detector

Directional direct detection of

**dark****matter**is expected to be a hopeful way to discriminate isotropic distribution from anisotropic one. Expand abstract. Velocity distribution of

**dark****matter**is supposed to be isotropic Maxwell-Boltzmann distribution in most cases, however, other distribution models including anisotropic one are suggested by simulations. Directional direct detection of**dark****matter**is expected to be a hopeful way to discriminate isotropic distribution from anisotropic one. We investigate the possibility to obtain the anisotropy and WIMP mass by Monte-Carlo simulation supposing the directional detector.4 days ago

10/10 relevant

arXiv

10/10 relevant

arXiv

Towards A UV-Model of Kinetic Mixing and Portal **Matter**

The nature of dark matter (DM) and how it might interact with the particles of the Standard Model (SM) is an ever-growing mystery. Expand abstract.

The nature of

**dark****matter**(DM) and how it might interact with the particles of the Standard Model (SM) is an ever-growing mystery. It is possible that the existence of new `dark sector' forces, yet undiscovered, are the key to solving this fundamental problem, and one might hope that in the future such forces might even be `unified' with the ones we already know in some UV-complete framework. In this paper, following a bottom-up approach, we attempt to take the first steps in the construction of such a framework. The much-discussed possibility of the kinetic mixing (KM) of the `dark photon' with the hypercharge gauge boson of the SM via loops of portal**matter**(PM) fields, charged in both sectors, offers an attractive starting point for these efforts. Given the anticipated finite strength of the KM in a UV-complete theory, the absence of anomalies, and the lifetime constraints on the PM fields arising from CMB and nucleosynthesis constraints, PM must behave as vector-like copies of the known SM fermion fields, such as those which appear naturally in $E_6$-type models. Within such a setup, the SM and their corresponding partner PM fields would be related by a new $SU(2)_I$ gauge symmetry. With this observation as a springboard, we construct a generalization of these ideas where $SU(2)_I$ is augmented by an additional $U(1)_{I_Y}$ factor so that the light**dark**photon is the result of a symmetry breaking analogous to the SM, \ie, $SU(2)_I\times U(1)_{I_Y}\to U(1)_D$, but with $U(1)_D$ now also broken at the $\lesssim$ GeV scale. While SM fields are $U(1)_D$ singlets, as in the conventional**dark**photon approach, they transform nontrivially under the full $SU(2)_I\times U(1)_{I_Y}$ gauge group. This approach leads to numerous interesting signatures, both at low energies and at colliders, and can be viewed as an initial step in the construction of a more UV-complete framework.4 days ago

4/10 relevant

arXiv

4/10 relevant

arXiv

Direct detection and complementary constraints for sub-GeV **dark** **matter**

Finally we stress that

**dark****matter**self-interactions place stringent limits independently of the dark matter production mechanism. Expand abstract. Traditional direct searches for

**dark**matter, looking for nuclear recoils in deep underground detectors, are challenged by an almost complete loss of sensitivity for light**dark****matter**particles. Consequently, there is a significant effort in the community to devise new methods and experiments to overcome these difficulties, constantly pushing the limits of the lowest**dark****matter**mass that can be probed this way. From a model-building perspective, the scattering of sub-GeV**dark****matter**on nucleons essentially must proceed via new light mediator particles, given that collider searches place extremely stringent bounds on contact-type interactions. Here we present an updated compilation of relevant limits for the case of a scalar mediator, including a new estimate of the near-future sensitivity of the NA62 experiment as well as a detailed evaluation of limits from Big Bang nucleosynthesis. We also derive updated and more general limits on DM particles upscattered by cosmic rays, applicable to arbitrary energy- and momentum dependences of the scattering cross section. Finally we stress that**dark****matter**self-interactions place stringent limits independently of the**dark****matter**production mechanism. These are, for the relevant parameter space, generically comparable to those that apply in the commonly studied freeze-out case. We conclude that the combination of existing (or expected) constraints from accelerators and astrophysics, combined with cosmological requirements, puts robust limits on the maximally possible nuclear scattering rate. In most regions of parameter space these are at least competitive with the best projected limits from currently planned direct detection experiments.5 days ago

10/10 relevant

arXiv

10/10 relevant

arXiv

LHC phenomenology with hidden sector **dark** **matter**: a long-lived stau and
heavy Higgs in an observable range

The presence of a hidden sector with very weak interactions with the standard model has significant implications on LHC signatures. Expand abstract.

The presence of a hidden sector with very weak interactions with the standard model has significant implications on LHC signatures. In this work we discuss LHC phenomenology with the inclusion of a hidden sector by a $U(1)$ extension of MSSM/SUGRA. We consider both kinetic mixing and Stueckelberg mass mixing between the $U(1)$ gauge field of the hidden sector and $U(1)_Y$ of the visible sector. Such a model has an extended parameter space. We consider here two limited regions of this parameter space. In the first case we consider a $U(1)$ gauge field along with chiral fields needed for the Stueckelberg mechanism to operate and discuss the mixing between the hidden and the visible sectors. Here if the stau is the lightest sparticle in the MSSM sector and the neutralino of the hidden sector is the LSP of the full system and a

**dark****matter**candidate, the stau can be long-lived and decay inside an LHC detector tracker. In the second case we include extra vectorlike**matter**in the hidden sector which can give rise to a Dirac fermion in addition to the two neutralinos in the hidden sector. The neutralino sector now has six neutralinos and we assume that the lightest of these is the LSP and is higgsino-like. In this case the**dark****matter**is constituted of a Majorana and a Dirac fermion, and a small $\mu$ leads to heavy Higgs boson masses which reside in the observable range of HL-LHC and HE-LHC.5 days ago

10/10 relevant

arXiv

10/10 relevant

arXiv

A radiative seesaw model with GeV singlet-doublet fermion and TeV
triplet scalar **dark** **matter**

By extending the Standard Model with singlet-doublet fermions and triplet scalars, all odd under a new $Z_2$ symmetry, we introduce a radiative seesaw model that can simultaneously account for dark matter, explain the existence of neutrino masses and allow for gauge coupling unification. Expand abstract.

By extending the Standard Model with singlet-doublet fermions and triplet scalars, all odd under a new $Z_2$ symmetry, we introduce a radiative seesaw model that can simultaneously account for

**dark**matter, explain the existence of neutrino masses and allow for gauge coupling unification. We explore the viable parameter space of the model after imposing collider, Higgs mass,**dark**matter, neutrino mass and lepton flavour violation constraints. We find that**dark****matter**in this model is fermionic for masses below about 1 TeV and scalar above and observe a high degree of complementarity between direct detection and lepton flavour violation experiments, which should soon allow to fully probe the fermionic**dark****matter**sector and at least partially the scalar**dark****matter**sector.10 days ago

10/10 relevant

arXiv

10/10 relevant

arXiv

Can EDGES observation favour any **dark** **matter** model?

We show that all these

**dark****matter**models cannot be statistically distinguished using the available EDGES data. Expand abstract. The recent detection of the 21-cm absorption signal by the EDGES collaboration has been widely used to constrain the basic properties of

**dark****matter**particles. However, extracting the parameters of the 21-cm absorption signal relies on a chosen parametrisation of the foreground radio emission. Recently, the new parametrisations of the foreground and systematics have been proposed, showing significant deviations of the 21-cm signal parameters from those assumed by the original EDGES paper. In this paper, we consider this new uncertainty, comparing the observed signal with the predictions of several**dark****matter**models, including the widely-used cold**dark****matter**(CDM) model, 1-3 keV warm**dark****matter**models (WDM), and 7 keV sterile neutrino (SN7) model, capable of producing the reported 3.5 keV line. We show that all these**dark****matter**models cannot be statistically distinguished using the available EDGES data.10 days ago

10/10 relevant

arXiv

10/10 relevant

arXiv

Neural physical engines for inferring the halo mass distribution function

As a result, we are able to sample the initial phases of the

**dark****matter**density field whilst inferring the parameters describing the halo mass distribution function, providing a fully Bayesian interpretation of both the initial dark matter density distribution and the neural bias model. Expand abstract. An ambitious goal in cosmology is to forward-model the observed distribution of galaxies in the nearby Universe today from the initial conditions of large-scale structures. For practical reasons, the spatial resolution at which this can be done is necessarily limited. Consequently, one needs a mapping between the density of

**dark****matter**averaged over ~Mpc scales, and the distribution of**dark****matter**halos (used as a proxy for galaxies) in the same region. Here we demonstrate a method for determining the halo mass distribution function by learning the tracer bias between density fields and halo catalogues using a neural bias model. The method is based on the Bayesian analysis of simple, physically motivated, neural network-like architectures, which we denote as neural physical engines, and neural density estimation. As a result, we are able to sample the initial phases of the**dark****matter**density field whilst inferring the parameters describing the halo mass distribution function, providing a fully Bayesian interpretation of both the initial**dark****matter**density distribution and the neural bias model. We successfully run an upgraded BORG inference using our new likelihood and neural bias model with halo catalogues derived from full N-body simulations. We notice orders of magnitude improvement in modelling compared to classical biasing techniques.10 days ago

5/10 relevant

arXiv

5/10 relevant

arXiv

Dynamical Friction in a Fuzzy **Dark** **Matter** Universe

We present an in-depth exploration of the phenomenon of dynamical friction in a universe where the dark matter is composed entirely of so-called Fuzzy Dark Matter (FDM), ultralight bosons of mass $m\sim\mathcal{O}(10^{-22})\,$eV. Expand abstract.

We present an in-depth exploration of the phenomenon of dynamical friction in a universe where the

**dark****matter**is composed entirely of so-called Fuzzy**Dark****Matter**(FDM), ultralight bosons of mass $m\sim\mathcal{O}(10^{-22})\,$eV. We review the classical treatment of dynamical friction before presenting analytic results in the case of FDM for point masses, extended mass distributions, and FDM backgrounds with finite velocity dispersion. We then test these results against a large suite of fully non-linear simulations that allow us to assess the regime of applicability of the analytic results. We apply these results to a variety of astrophysical problems of interest, including infalling satellites in a galactic**dark****matter**background, and determine that \emph{(1)}~for FDM masses $m\gtrsim 10^{-21}\, {\rm eV}\, c^{-2}$, the timing problem of the Fornax dwarf spheroidal's globular clusters is no longer solved and \emph{(2)}~the effects of FDM on the process of dynamical friction for satellites of total mass $M$ and relative velocity $v_{\rm rel}$ should require detailed numerical simulations for $\left(M/10^9~M_{\odot}\right) \left(m/10^{-22}~{\rm eV}\right)\left(100~{\rm km}~{\rm s}^{-1}/v_{\rm rel}\right) \sim 1$, parameters which would lie outside the validated range of applicability of any currently developed analytic theory, due to transient wave structures in the time-dependent regime.10 days ago

10/10 relevant

arXiv

10/10 relevant

arXiv

A theory for scotogenic **dark** **matter** stabilised by residual gauge
symmetry

Dark matter stability can result from a residual matter-parity symmetry, following naturally from the spontaneous breaking of the gauge symmetry. Expand abstract.

**Dark**

**matter**stability can result from a residual

**matter**-parity symmetry, following naturally from the spontaneous breaking of the gauge symmetry. Here we explore this idea in the context of the $\mathrm{SU(3)_c \otimes SU(3)_L \otimes U(1)_X \otimes U(1)_{N}}$ electroweak extension of the standard model. The key feature of our new scotogenic

**dark**

**matter**theory is the use of a triplet scalar boson with anti-symmetric Yukawa couplings. This naturally implies that one of the light neutrinos is massless and, as a result, there is a lower bound for the $\rm 0\nu\beta\beta$ decay rate.

10 days ago

10/10 relevant

arXiv

10/10 relevant

arXiv