scholarly journals Electroweak phase transition with an SU(2) dark sector

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Tathagata Ghosh ◽  
Huai-Ke Guo ◽  
Tao Han ◽  
Hongkai Liu
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Cold Dark Matter ◽  
Signal To Noise Ratio ◽  
Small Scale ◽  
Model Parameters ◽  
Dark Sector ◽  
Electroweak Phase Transition ◽  
The Rich ◽  
Higgs Portal

Abstract We consider a non-Abelian dark SU(2)D model where the dark sector couples to the Standard Model (SM) through a Higgs portal. We investigate two different scenarios of the dark sector scalars with Z2 symmetry, with Higgs portal interactions that can introduce mixing between the SM Higgs boson and the SM singlet scalars in the dark sector. We utilize the existing collider results of the Higgs signal rate, direct heavy Higgs searches, and electroweak precision observables to constrain the model parameters. The SU(2)D partially breaks into U(1)D gauge group by the scalar sector. The resulting two stable massive dark gauge bosons and pseudo-Goldstone bosons can be viable cold dark matter candidates, while the massless gauge boson from the unbroken U(1)D subgroup is a dark radiation and can introduce long-range attractive dark matter (DM) self-interaction, which can alleviate the small-scale structure issues. We study in detail the pattern of strong first-order phase transition and gravitational wave (GW) production triggered by the dark sector symmetry breaking, and further evaluate the signal-to-noise ratio for several proposed space interferometer missions. We conclude that the rich physics in the dark sector may be observable with the current and future measurements at colliders, DM experiments, and GW interferometers.

scholarly journals Dark Matter production from relativistic bubble walls

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Aleksandr Azatov ◽  
Miguel Vanvlasselaer ◽  
Wen Yin
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Electroweak Phase Transition ◽  
First Order ◽  
Matter Production ◽  
First Order Phase Transition ◽  
Relic Abundance ◽  
Higgs Portal ◽  
First Order Phase ◽  
Gravitational Background

Abstract In this paper we present a novel mechanism for producing the observed Dark Matter (DM) relic abundance during the First Order Phase Transition (FOPT) in the early universe. We show that the bubble expansion with ultra-relativistic velocities can lead to the abundance of DM particles with masses much larger than the scale of the transition. We study this non-thermal production mechanism in the context of a generic phase transition and the electroweak phase transition. The application of the mechanism to the Higgs portal DM as well as the signal in the Stochastic Gravitational Background are discussed.

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 Cold dark matter: Controversies on small scales

2015 ◽  
Vol 112 (40) ◽  
pp. 12249-12255 ◽  
Author(s):  
David H. Weinberg ◽  
James S. Bullock ◽  
Fabio Governato ◽  
Rachel Kuzio de Naray ◽  
Annika H. G. Peter
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Cold Dark Matter ◽  
Dwarf Galaxy ◽  
Analytical Models ◽  
Small Scale ◽  
Dark Sector ◽  
Massive Galaxies ◽  
Galaxy Dynamics ◽  
Wide Range

The cold dark matter (CDM) cosmological model has been remarkably successful in explaining cosmic structure over an enormous span of redshift, but it has faced persistent challenges from observations that probe the innermost regions of dark matter halos and the properties of the Milky Way’s dwarf galaxy satellites. We review the current observational and theoretical status of these “small-scale controversies.” Cosmological simulations that incorporate only gravity and collisionless CDM predict halos with abundant substructure and central densities that are too high to match constraints from galaxy dynamics. The solution could lie in baryonic physics: Recent numerical simulations and analytical models suggest that gravitational potential fluctuations tied to efficient supernova feedback can flatten the central cusps of halos in massive galaxies, and a combination of feedback and low star formation efficiency could explain why most of the dark matter subhalos orbiting the Milky Way do not host visible galaxies. However, it is not clear that this solution can work in the lowest mass galaxies, where discrepancies are observed. Alternatively, the small-scale conflicts could be evidence of more complex physics in the dark sector itself. For example, elastic scattering from strong dark matter self-interactions can alter predicted halo mass profiles, leading to good agreement with observations across a wide range of galaxy mass. Gravitational lensing and dynamical perturbations of tidal streams in the stellar halo provide evidence for an abundant population of low-mass subhalos in accord with CDM predictions. These observational approaches will get more powerful over the next few years.

scholarly journals Inelastic dark matter, small scale problems, and the XENON1T excess

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Seungwon Baek
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Gauge Coupling ◽  
Photoelectric Effect ◽  
Elastic Cross Section ◽  
Small Scale ◽  
Generic Model ◽  
Dark Sector ◽  
Relic Abundance ◽  
Inelastic Dark Matter

Abstract We study a generic model in which the dark sector is composed of a Majorana dark matter χ1, its excited state χ2, both at the electroweak scale, and a light dark photon Z′ with mz′ ∼ 10−4 eV. The light Z′ enhances the self-scattering elastic cross section χ1χ1 → χ1χ1 enough to solve the small scale problems in the N-body simulations with the cold dark matter. The dark matter communicates with the SM via kinetic mixing parameterized by ϵ. The inelastic scattering process χ1χ1 → χ2χ2 followed by the prompt decay χ2 → χ1Z′ generates energetic Z′. By setting δ ≡ mχ2− mχ1 ≃ 2.8 keV and ϵ ∼ 10−10 the excess in the electron-recoil data at the XENON1T experiment can be explained by the dark-photoelectric effect. The relic abundance of the dark matter can also be accommodated by the thermal freeze-out mechanism via the annihilation χ1χ1(χ2χ2) → Z′Z′ with the dark gauge coupling constant αX ∼ 10−3.

scholarly journals Inert dark matter and strong electroweak phase transition

2012 ◽  
Vol 717 (4-5) ◽  
pp. 396-402 ◽  
Author(s):  
Grzegorz Gil ◽  
Piotr Chankowski ◽  
Maria Krawczyk
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Electroweak Phase Transition

scholarly journals The Dark Sector in the Baryon Phase Transition Cosmology

2019 ◽  
Author(s):  
Frederick J. Mayer
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Dark Energy ◽  
Cosmological Model ◽  
Dark Sector

This brief communication considers and illustrates dark matter and dark energy within the Baryon Phase Transition (BPT) cosmological model as well as some experiments that may confirm (or deny) the validity of the model.

scholarly journals Heating of Milky Way disc stars by dark matter fluctuations in cold dark matter and fuzzy dark matter paradigms

2019 ◽  
Vol 485 (2) ◽  
pp. 2861-2876 ◽  
Author(s):  
Benjamin V Church ◽  
Philip Mocz ◽  
Jeremiah P Ostriker
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Quantum Interference ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Velocity Dispersion ◽  
Formation Rate ◽  
Density Fluctuations ◽  
Particle Mass ◽  
Small Scale

ABSTRACT Although highly successful on cosmological scales, cold dark matter (CDM) models predict unobserved overdense ‘cusps’ in dwarf galaxies and overestimate their formation rate. We consider an ultralight axion-like scalar boson which promises to reduce these observational discrepancies at galactic scales. The model, known as fuzzy dark matter (FDM), avoids cusps, suppresses small-scale power, and delays galaxy formation via macroscopic quantum pressure. We compare the substructure and density fluctuations of galactic dark matter haloes comprised of ultralight axions to conventional CDM results. Besides self-gravitating subhaloes, FDM includes non-virialized overdense wavelets formed by quantum interference patterns, which are an efficient source of heating to galactic discs. We find that, in the solar neighbourhood, wavelet heating is sufficient to give the oldest disc stars a velocity dispersion of ${\sim } {30}{\, \mathrm{km\, s}^{-1}}$ within a Hubble time if energy is not lost from the disc, the velocity dispersion increasing with stellar age as σD ∝ t0.4 in agreement with observations. Furthermore, we calculate the radius-dependent velocity dispersion and corresponding scaleheight caused by the heating of this dynamical substructure in both CDM and FDM with the determination that these effects will produce a flaring that terminates the Milky Way disc at $15\!-\!20{\, \mathrm{kpc}}$. Although the source of thickened discs is not known, the heating due to perturbations caused by dark substructure cannot exceed the total disc velocity dispersion. Therefore, this work provides a lower bound on the FDM particle mass of ma > 0.6 × 10−22 eV. Furthermore, FDM wavelets with this particle mass should be considered a viable mechanism for producing the observed disc thickening with time.

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