scholarly journals When freeze-out occurs due to a non-Boltzmann suppression: a study of degenerate dark sector

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Anirban Biswas ◽  
Sougata Ganguly ◽  
Sourov Roy
Keyword(s):  
Dark Matter ◽  
Direct Detection ◽  
Atmospheric Neutrino ◽  
Radioactive Decay ◽  
Number Density ◽  
Dark Sector ◽  
Dark Matter Annihilation ◽  
Cascade Processes ◽  
Chemical Imbalance ◽  
Freeze Out

Abstract Exponential suppression or commonly known as the Boltzmann suppression in the number density of dark matter is the key ingredient for creating chemical imbalance prior to the usual thermal freeze-out. A degenerate/quasi-degenerate dark sector can experience a different exponential suppression in the number density analogous to the radioactive decay law leading to a delayed freeze-out mechanism of dark matter known as the co-decaying dark matter. In this work, we study the dynamics of a multicomponent dark matter from thermally decoupled degenerate dark sector in a hidden U(1)X extension of the Standard Model. We compute the relic density of dark matter frozen-out through the co-decaying mechanism by solving four coupled Boltzmann equations. We demonstrate how temperature T′ of the dark sector changes due to all types of 3 → 2 and 2 → 2 interactions along with the eternal expansion of the Universe. We find that 3 → 2 interactions enhance T′ by producing energetic particles in the dark sector while the excess heat is transferred by 2 → 2 interactions to the entire dark sector. As the direct detection is possible only through the feeble portal couplings, we investigate the neutrino and γ-ray signals from dark matter annihilation via one step cascade processes and compare our results with the measured fluxes of atmospheric neutrinos by Super-Kamiokande and diffuse γ-rays by Fermi-LAT, EGRET, INTEGRAL collaborations. We find that the present scenario easily evades all the existing bounds from atmospheric neutrino and diffuse γ-ray observations for degenerate dark sector. However, the constraints are significant for quasi degenerate scenario.

scholarly journals A dark clue to seesaw and leptogenesis in a pseudo-Dirac singlet doublet scenario with (non)standard cosmology

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Partha Konar ◽  
Ananya Mukherjee ◽  
Abhijit Kumar Saha ◽  
Sudipta Show
Keyword(s):  
Dark Matter ◽  
Thermal History ◽  
Direct Detection ◽  
Critical Role ◽  
Mass Term ◽  
Baryon Asymmetry ◽  
Dark Sector ◽  
Lepton Asymmetry ◽  
History Of ◽  
The Universe

Abstract We propose an appealing alternative scenario of leptogenesis assisted by dark sector which leads to the baryon asymmetry of the Universe satisfying all theoretical and experimental constraints. The dark sector carries a non minimal set up of singlet doublet fermionic dark matter extended with copies of a real singlet scalar field. A small Majorana mass term for the singlet dark fermion, in addition to the typical Dirac term, provides the more favourable dark matter of pseudo-Dirac type, capable of escaping the direct search. Such a construction also offers a formidable scope to radiative generation of active neutrino masses. In the presence of a (non)standard thermal history of the Universe, we perform the detailed dark matter phenomenology adopting the suitable benchmark scenarios, consistent with direct detection and neutrino oscillations data. Besides, we have demonstrated that the singlet scalars can go through CP-violating out of equilibrium decay, producing an ample amount of lepton asymmetry. Such an asymmetry then gets converted into the observed baryon asymmetry of the Universe through the non-perturbative sphaleron processes owing to the presence of the alternative cosmological background considered here. Unconventional thermal history of the Universe can thus aspire to lend a critical role both in the context of dark matter as well as in realizing baryogenesis.

scholarly journals Collider constraints on dark mediators

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Hanna Mies ◽  
Christiane Scherb ◽  
Pedro Schwaller
Keyword(s):  
Dark Matter ◽  
Parameter Space ◽  
First Generation ◽  
Direct Detection ◽  
Full Range ◽  
Dark Matter Candidate ◽  
Dark Sector ◽  
Missing Energy ◽  
First Time

Abstract We explore the constraints current collider searches place on a QCD-like dark sector. A combination of multi-jet, multi-jet plus missing energy and emerging jets searches is used to derive constraints on the mediator mass across the full range of the dark meson lifetimes for the first time.The dark sector inherits a flavour structure from the coupling between the dark quarks and the SM quarks through the mediator. When this is taken into account, the differently flavoured dark pions become distinguishable through their lifetime. We show that also in these cases the above mentioned searches remain sensitive, and we obtain limits on the mediator mass also for the flavoured scenario.We then contrast the constraints from collider searches with direct detection bounds on the dark matter candidate itself in both the flavoured and unflavoured scenario. Using a simple prescription it becomes possible to display all constraints in the dark matter and mediator mass plane. Constraints from direct detection tend to be stronger than the collider constraints, unless the coupling to the first generation quarks is suppressed, in which case the collider searches place the most stringent limits on the parameter space.

scholarly journals Dark matter to baryon ratio from scalar triplets decay in type-II seesaw

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
Nimmala Narendra ◽  
Narendra Sahu ◽  
Sujay Shil
Keyword(s):  
Dark Matter ◽  
Particle Physics ◽  
Direct Detection ◽  
Dirac Fermion ◽  
Model Parameters ◽  
Type Ii ◽  
Dark Sector ◽  
Coincidence Problem ◽  
Electroweak Phase Transition ◽  
Visible Sector

AbstractWe propose a minimal model for the cosmic coincidence problem $$\Omega _\mathrm{DM}/\Omega _B \sim 5$$ Ω DM / Ω B ∼ 5 and neutrino mass in a type-II seesaw scenario. We extend the standard model of particle physics with a $$\mathrm SU(2)$$ S U ( 2 ) singlet leptonic Dirac fermion $$\chi $$ χ , which represents the candidate of dark matter (DM), and two triplet scalars $$\Delta _{1,2}$$ Δ 1 , 2 with hierarchical masses. In the early Universe, the CP violating out-of-equilibrium decay of lightest $$\Delta $$ Δ generates a net $$B-L$$ B - L asymmetry in the visible sector (comprising of SM fields), where B and L represents the total baryon and lepton number respectively. A part of this asymmetry gets transferred to the dark sector (comprising of DM $$\chi $$ χ ) through a dimension eight operator which conserves $$B-L$$ B - L . Above the electroweak phase transition, the $$B-L$$ B - L asymmetry of the visible sector gets converted to a net B-asymmetry by the $$B+L$$ B + L violating sphalerons, while the $$B-L$$ B - L asymmetry of the dark sector remains untouched which we see today as relics of DM. We show that the observed DM abundance can be explained for a DM mass about 8 GeV. We then introduce an additional singlet scalar field $$\phi $$ ϕ which mixes with the SM-Higgs to annihilate the symmetric component of the DM resonantly which requires the singlet scalar mass to be twice the DM mass, i.e. around 16 GeV, which can be searched at collider experiments. In our model, the active neutrinos also get small masses by the induced vacuum expectation value (vev) of the triplet scalars $$\Delta _{1,2}$$ Δ 1 , 2 . In the later part of the paper we discuss all the constraints on model parameters coming from invisible Higgs decay, Higgs signal strength, DM direct detection and relic density of DM.

scholarly journals Thermal relic of self-interacting dark matter with retarded decay of mediator

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Bin Zhu ◽  
Murat Abdughani
Keyword(s):  
Dark Matter ◽  
Direct Detection ◽  
Large Mass ◽  
Bound State ◽  
Blind Spot ◽  
Mass Splitting ◽  
Temperature Evolution ◽  
S Wave ◽  
Sommerfeld Enhancement ◽  
Freeze Out

Abstract The existence of a light mediator is beneficial to some phenomena in astroparticle physics, such as the core-cusp problem and diversity problem. It can decouple from Standard Model to avoid direct detection constraints, generally realized by retard decay of the mediator. Their out-of-equilibrium decay process changes the dark matter (DM) freeze-out via temperature discrepancy. This type of hidden sector (HS) typically requires a precision calculation of the freeze-out process considering HS temperature evolution and the thermal average of the cross-section. If the mediator is light sufficiently, we can not ignore the s-wave radiative bound state formation process from the perspective of CMB ionization and Sommerfeld enhancement. We put large mass splitting between DM and mediator, different temperature evolution on the same theoretical footing, discussing the implication for DM relic density in this HS. We study this model and illustrate its property by considering the general Higgs-portal dark matter scenario, which includes all the relevant constraints and signals. It shows that the combination of BBN and CMB constraint favors the not-too-hot HS, rinf< 102, for the positive cubic interaction of mediator scenario. On the other hand, the negative cubic interaction is ruled out except for our proposed blind spot scenario.

DARK MATTER ANNIHILATION IN THE LATE UNIVERSE

2008 ◽  
Vol 23 (17n20) ◽  
pp. 1643-1648
Author(s):  
NICOLE F. BELL
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Galactic Halo ◽  
Atmospheric Neutrino ◽  
Mass Range ◽  
Annihilation Cross Section ◽  
Dark Matter Annihilation ◽  
Unitarity Bound ◽  
Dark Matter Mass ◽  
Positron Flux

We examine dark matter annihilation in the Universe today. We first discuss the suggestion that the Galactic positron flux, which is difficult to account for with astrophysical sources, is produced by the annihilation of dark matter in the Galactic halo. We show that the positrons produced would necessarily be accompanied by a flux of gamma rays which exceed observational constraints, unless the dark matter mass is very low. We shall also derive a very general bond on the dark matter annihilation cross section. By considering annihilation into all Standard Model particles, we show that the least detectable final states, namely neutrinos, define an upper bound on the total annihilation cross section. Calculating the cosmic diffuse neutrino signal, and comparing it to the measured terrestrial atmospheric neutrino background, we derive a robust limit that is much stronger than the unitarity bound in the most interesting mass range. We conclude that dark matter self-annihilation rates cannot be large enough to have a significant effect on the density profiles of dark matter halos.

scholarly journals Heavy dark matter through the dilaton portal

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Benjamin Fuks ◽  
Mark D. Goodsell ◽  
Dong Woo Kang ◽  
Pyungwon Ko ◽  
Seung J. Lee ◽  
...  
Keyword(s):  
Dark Matter ◽  
Direct Detection ◽  
Effective Field ◽  
Matter Density ◽  
Field Theories ◽  
Majorana Fermion ◽  
Dark Sector ◽  
Gauge Invariant ◽  
Matter Production ◽  
Invariant Formulation

Abstract We re-examine current and future constraints on a heavy dilaton coupled to a simple dark sector consisting of a Majorana fermion or a Stückelberg vector field. We include three different treatments of dilaton-Higgs mixing, paying particular attention to a gauge-invariant formulation of the model. Moreover, we also invite readers to re-examine effective field theories of vector dark matter, which we show are missing important terms. Along with the latest Higgs coupling data, heavy scalar search results, and dark matter density/direct detection constraints, we study the LHC bounds on the model and estimate the prospects of dark matter production at the future HL-LHC and 100 TeV FCC colliders. We additionally compute novel perturbative unitarity constraints involving vector dark matter, dilaton and gluon scattering.

scholarly journals Halo-independent tests of dark matter direct detection signals: local DM density, LHC, and thermal freeze-out

2015 ◽  
Vol 2015 (08) ◽  
pp. 039-039 ◽  
Author(s):  
Mattias Blennow ◽  
Juan Herrero-Garcia ◽  
Thomas Schwetz ◽  
Stefan Vogl
Keyword(s):  
Dark Matter ◽  
Direct Detection ◽  
Freeze Out

scholarly journals Thermal real scalar triplet dark matter

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Taisuke Katayose ◽  
Shigeki Matsumoto ◽  
Satoshi Shirai ◽  
Yu Watanabe
Keyword(s):  
Dark Matter ◽  
Direct Detection ◽  
The Other ◽  
Indirect Detection ◽  
Sommerfeld Effect ◽  
Dark Matter Annihilation ◽  
Parameter Region ◽  
Real Scalar ◽  
Attractive Candidate ◽  
Near Future

Abstract Real scalar triplet dark matter, which is known to be an attractive candidate for a thermal WIMP, is comprehensively studied paying particular attention to the Sommerfeld effect on the dark matter annihilation caused by the weak interaction and the other interaction between the dark matter and the Higgs boson. We find a parameter region that includes the so-called ‘WIMP-Miracle’ one is still surviving, i.e. it respects all constraints imposed by dark matter searches at collider experiments, underground experiments (direct detection) and astrophysical observations (indirect detection). The region is also found to be efficiently searched for by various near future experiments. In particular, the XENONnT experiment will cover almost the entire parameter region.

scholarly journals Dark QED from inflation

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Asimina Arvanitaki ◽  
Savas Dimopoulos ◽  
Marios Galanis ◽  
Davide Racco ◽  
Olivier Simon ◽  
...  
Keyword(s):  
Dark Matter ◽  
Strong Field ◽  
Direct Detection ◽  
Mass Range ◽  
Electron Mass ◽  
Dark Sector ◽  
Plasma Dynamics ◽  
Weakly Coupled ◽  
The Standard Model ◽  
Enormous Number

Abstract One contribution to any dark sector’s abundance comes from its gravitational production during inflation. If the dark sector is weakly coupled to the inflaton and the Standard Model, this can be its only production mechanism. For non-interacting dark sectors, such as a free massive fermion or a free massive vector field, this mechanism has been studied extensively. In this paper we show, via the example of dark massive QED, that the presence of interactions can result in a vastly different mass for the dark matter (DM) particle, which may well coincide with the range probed by upcoming experiments.In the context of dark QED we study the evolution of the energy density in the dark sector after inflation. Inflation produces a cold vector condensate consisting of an enormous number of bosons, which via interesting processes — Schwinger pair production, strong field electromagnetic cascades, and plasma dynamics — transfers its energy to a small number of “dark electrons” and triggers thermalization of the dark sector. The resulting dark electron DM mass range is from 50 MeV to 30 TeV, far different from both the 10−5 eV mass of the massive photon dark matter in the absence of dark electrons, and from the 109 GeV dark electron mass in the absence of dark photons. This can significantly impact the search strategies for dark QED and, more generally, theories with a self-interacting DM sector. In the presence of kinetic mixing, a dark electron in this mass range can be searched for with upcoming direct detection experiments, such as SENSEI-100g and OSCURA.

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