scholarly journals An update on the two singlet dark matter model

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Tanushree Basak ◽  
Baradhwaj Coleppa ◽  
Kousik Loho

Abstract We revisit the two real singlet extension of the Standard Model with a $$ {Z}_2\times {Z}_2^{\prime } $$ Z 2 × Z 2 ′ symmetry. One of the singlet scalars S2, by virtue of an unbroken $$ {Z}_2^{\prime } $$ Z 2 ′ symmetry, plays the role of a stable dark matter candidate. The other scalar S1, with spontaneously broken Z2-symmetry, mixes with the SM Higgs boson and acts as the scalar mediator. We analyze the model by putting in the entire set of theoretical and recent experimental constraints. The latest bounds from direct detection Xenon1T experiment severely restricts the allowed region of parameter space of couplings. To ensure the dark matter satisfies the relic abundance criterion, we rely on the Breit-Wigner enhanced annihilation cross-section. Further, we study the viability of explaining the observed gamma-ray excess in the galactic center in this model with a dark matter of mass in the ∼ 36 − 51 GeV window and present our conclusions.

2016 ◽  
Vol 2016 (03) ◽  
pp. 048-048 ◽  
Author(s):  
Shunsaku Horiuchi ◽  
Oscar Macias ◽  
Diego Restrepo ◽  
Andrés Rivera ◽  
Oscar Zapata ◽  
...  

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Bastián Díaz Sáez ◽  
Patricio Escalona ◽  
Sebastián Norero ◽  
Alfonso Zerwekh

Abstract We explore a simple extension to the Standard Model containing two gauge singlets: a Dirac fermion and a real pseudoscalar. In some regions of the parameter space both singlets are stable without the necessity of additional symmetries, then becoming a possible two-component dark matter model. We study the relic abundance production via freeze-out, with the latter determined by annihilations, conversions and semi-annihilations. Experimental constraints from invisible Higgs decay, dark matter relic abundance and direct/indirect detection are studied. We found three viable regions of the parameter space, and the model is sensitive to indirect searches.


2008 ◽  
Vol 23 (26) ◽  
pp. 2125-2140 ◽  
Author(s):  
R. BERNABEI ◽  
P. BELLI ◽  
F. CAPPELLA ◽  
R. CERULLI ◽  
C. J. DAI ◽  
...  

Some extensions of the Standard Model provide Dark Matter candidate particles with sub-GeV mass. These Light Dark Matter particles have been considered for example in Warm Dark Matter scenarios (e.g. the keV scale sterile neutrino, axino or gravitino). Moreover, MeV scale DM candidates have been proposed in supersymmetric models and as source of the 511 keV line from the Galactic center. In this paper the possibility of direct detection of a Light Dark Matter candidate is investigated considering the inelastic scattering processes on the electron or on the nucleus targets. Some theoretical arguments are developed and related phenomenological aspects are discussed. Allowed volumes and regions for the characteristic phenomenological parameters of the considered scenarios are derived from the DAMA/NaI annual modulation data.


2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Chih-Ting Lu ◽  
Raymundo Ramos ◽  
Yue-Lin Sming Tsai

Abstract Recently, we have witnessed two hints of physics beyond the standard model: a 3.3σ local excess ($$ {M}_{A_0} $$ M A 0 = 52 GeV) in the search for H0 → A0A0 → b$$ \overline{b} $$ b ¯ μ+μ− and a 4.2σ deviation from the SM prediction in the (g − 2)μ measurement. The first excess was found by the ATLAS collaboration using 139 fb−1 data at $$ \sqrt{s} $$ s = 13 TeV. The second deviation is a combination of the results from the Brookhaven E821 and the recently reported Fermilab E989 experiment. We attempt to explain these deviations in terms of a renormalizable simplified dark matter model. Inspired by the null signal result from dark matter (DM) direct detection, we interpret the possible new particle, A0, as a pseudoscalar mediator connecting DM and the standard model. On the other hand, a new vector-like muon lepton can explain these two excesses at the same time while contributing to the DM phenomenology.


Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1432
Author(s):  
Dmitry O. Chernyshov ◽  
Andrei E. Egorov ◽  
Vladimir A. Dogiel ◽  
Alexei V. Ivlev

Recent observations of gamma rays with the Fermi Large Area Telescope (LAT) in the direction of the inner galaxy revealed a mysterious excess of GeV. Its intensity is significantly above predictions of the standard model of cosmic rays (CRs) generation and propagation with a peak in the spectrum around a few GeV. Popular interpretations of this excess are that it is due to either spherically distributed annihilating dark matter (DM) or an abnormal population of millisecond pulsars. We suggest an alternative explanation of the excess through the CR interactions with molecular clouds in the Galactic Center (GC) region. We assumed that the excess could be imitated by the emission of molecular clouds with depleted density of CRs with energies below ∼10 GeV inside. A novelty of our work is in detailed elaboration of the depletion mechanism of CRs with the mentioned energies through the “barrier” near the cloud edge formed by the self-excited MHD turbulence. This depletion of CRs inside the clouds may be a reason for the deficit of gamma rays from the Central Molecular Zone (CMZ) at energies below a few GeV. This in turn changes the ratio between various emission components at those energies and may potentially absorb the GeV excess by a simple renormalization of key components.


2021 ◽  
Vol 1719 (1) ◽  
pp. 012041
Author(s):  
Tanech Klangburam ◽  
Chakrit Pongkitivanichkul

2013 ◽  
Vol 87 (10) ◽  
Author(s):  
Masaki Asano ◽  
Torsten Bringmann ◽  
Günter Sigl ◽  
Martin Vollmann

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Shrihari Gopalakrishna ◽  
Tuhin Subhra Mukherjee

We study a gauge-singlet vector-like fermion hidden sector dark matter model, in which the communication between the dark matter and the visible standard model sector is via the Higgs-portal scalar-Higgs mixing and also via a hidden sector scalar with loop-level couplings to two gluons and also to two hypercharge gauge bosons induced by a vector-like quark. We find that the Higgs-portal possibility is stringently constrained to be small by the recent LHC di-Higgs search limits, and the loop induced couplings are important to include. In the model parameter space, we present the dark matter relic density, the dark-matter-nucleon direct detection scattering cross section, the LHC diphoton rate from gluon-gluon fusion, and the theoretical upper bounds on the fermion-scalar couplings from perturbative unitarity.


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