scholarly journals A first order dark SU(2) D phase transition with vector dark matter in the light of NANOGrav 12.5 yr data

2021 ◽  
Vol 2021 (12) ◽  
pp. 039
Author(s):  
Debasish Borah ◽  
Arnab Dasgupta ◽  
Sin Kyu Kang
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Scalar Potential ◽  
Dark Sector ◽  
Complex Scalar ◽  
First Order ◽  
First Order Phase Transition ◽  
Vector Bosons ◽  
Relic Abundance ◽  
First Order Phase

Abstract We study a dark SU(2) D gauge extension of the standard model (SM) with the possibility of a strong first order phase transition (FOPT) taking place below the electroweak scale in the light of NANOGrav 12.5 yr data. As pointed out recently by the NANOGrav collaboration, gravitational waves (GW) from such a FOPT with appropriate strength and nucleation temperature can explain their 12.5 yr data. We impose a classical conformal invariance on the scalar potential of SU(2) D sector involving only a complex scalar doublet with negligible couplings with the SM Higgs. While a FOPT at sub-GeV temperatures can give rise to stochastic GW around nano-Hz frequencies being in agreement with NANOGrav findings, the SU(2) D vector bosons which acquire masses as a result of the FOPT in dark sector, can also serve as dark matter (DM) in the universe. The relic abundance of such vector DM can be generated in a non-thermal manner from the SM bath via scalar portal mixing. We also discuss future sensitivity of gravitational wave experiments to the model parameter space.

scholarly journals Gravitational wave signals of dark matter freeze-out

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Danny Marfatia ◽  
Po-Yan Tseng
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Gravitational Waves ◽  
Order Phase Transition ◽  
First Order ◽  
Stochastic Background ◽  
First Order Phase Transition ◽  
Relic Abundance ◽  
First Order Phase ◽  
Freeze Out

Abstract We study the stochastic background of gravitational waves which accompany the sudden freeze-out of dark matter triggered by a cosmological first order phase transition that endows dark matter with mass. We consider models that produce the measured dark matter relic abundance via (1) bubble filtering, and (2) inflation and reheating, and show that gravitational waves from these mechanisms are detectable at future 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 as dark dwarfs and other macroscopic objects: multiverse relics?

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Christian Gross ◽  
Giacomo Landini ◽  
Alessandro Strumia ◽  
Daniele Teresi
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Bound States ◽  
Primordial Black Holes ◽  
False Vacuum ◽  
First Order ◽  
First Order Phase Transition ◽  
Macroscopic Objects ◽  
Chandrasekhar Limit ◽  
First Order Phase

Abstract First order phase transitions can leave relic pockets of false vacua and their particles, that manifest as macroscopic Dark Matter. We compute one predictive model: a gauge theory with a dark quark relic heavier than the confinement scale. During the first order phase transition to confinement, dark quarks remain in the false vacuum and get compressed, forming Fermi balls that can undergo gravitational collapse to stable dark dwarfs (bound states analogous to white dwarfs) near the Chandrasekhar limit, or primordial black holes.

SOME THOUGHTS ON THE COSMOLOGICAL QCD PHASE TRANSITION

2008 ◽  
Vol 23 (30) ◽  
pp. 4757-4777
Author(s):  
W-Y. P. HWANG
Keyword(s):  
Phase Transition ◽  
Scalar Field ◽  
Order Phase Transition ◽  
Domain Walls ◽  
Wall Structure ◽  
Complex Scalar ◽  
Qcd Phase Transition ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

The cosmological QCD phase transitions may have taken place between 10-5 s and 10-4 s in the early universe offers us one of the most intriguing and fascinating questions in cosmology. In bag models, the phase transition is described by the first-order phase transition and the role played by the latent "heat" or energy released in the transition is highly nontrivial and is being classified as the first-order phase transition. In this presentation, we assume, first of all, that the cosmological QCD phase transition, which happened at a time between 10-5 s and 10-4 s or at the temperature of about 150 MeV and accounts for confinement of quarks and gluons to within hadrons, would be of first-order. Of course, we may assume that the cosmological QCD phase transition may not be of the first-order. To get the essence out of the first-order scenario, it is sufficient to approximate the true QCD vacuum as one of possibly degenerate vacua and when necessary we try to model it effectively via a complex scalar field with spontaneous symmetry breaking. On the other hand, we may use a real scalar field in describing the non-first-order QCD phase transition. In the first-order QCD phase transition, we could examine how and when "pasted" or "patched" domain walls are formed, how long such walls evolve in the long run, and we believe that the significant portion of dark matter could be accounted for in terms of such domain-wall structure and its remnants. Of course, the cosmological QCD phase transition happened in the way such that the false vacua associated with baryons and many other color-singlet objects did not disappear (that is, using the bag-model language, there are bags of radius 1.0 fermi for the baryons) — but the amount of the energy remained in the false vacua is negligible by comparison. The latent energy released due to the conversion of the false vacua to the true vacua, in the form of "pasted" or "patched" domain walls in the short run and their numerous evolved objects, should make the concept of the "radiation-dominated" epoch, or of the "matter-dominated" epoch to be reexamined.

scholarly journals Filtered asymmetric dark matter during the Peccei-Quinn phase transition

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
M. Ahmadvand
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Gravitational Waves ◽  
Order Phase Transition ◽  
Annihilation Process ◽  
Density Spectrum ◽  
First Order ◽  
First Order Phase Transition ◽  
Asymmetric Dark Matter ◽  
First Order Phase

Abstract In this paper, we propose a bubble filtering-out mechanism for an asymmetric dark matter scenario during the Peccei-Quinn (PQ) phase transition. Based on a QCD axion model, extended by extra chiral neutrinos, we show that the PQ phase transition can be first order in the parameter space of the model and regarding the PQ symmetry breaking scale, the mechanism can generate PeV-scale heavy neutrinos as a dark matter candidate. Considering a CP-violating source, during the phase transition, discriminating between the neutrino and antineutrino number density, we find the observed dark matter relic abundance, such that the setup can be applied to the first order phase transition with different strengths. We then calculate effective couplings of the QCD axion addressing the strong CP problem within the model. We also study the energy density spectrum of gravitational waves generated from the first order phase transition and show that the signals can be detected by future ground-based detectors such as Einstein Telescope. In particular, for a visible heavy axion case of the model, it is shown that gravitational waves can be probed by DECIGO and BBO interferometers. Furthermore, we discuss the dark matter-standard model neutrino annihilation process as a source for the creation of PeV-scale neutrinos.

scholarly journals Searching for lepton portal dark matter with colliders and gravitational waves

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Jia Liu ◽  
Xiao-Ping Wang ◽  
Ke-Pan Xie
Keyword(s):  
Dark Matter ◽  
Higgs Boson ◽  
Scalar Potential ◽  
Majorana Fermion ◽  
Charged Scalar ◽  
First Order Phase Transition ◽  
Lepton Colliders ◽  
The Standard Model ◽  
Relic Abundance ◽  
First Order Phase

Abstract We study the lepton portal dark matter (DM) model in which the relic abundance is determined by the portal coupling among the Majorana fermion DM candidate χ, the singlet charged scalar mediator S± and the Standard Model (SM) right-handed lepton. The direct and indirect searches are not sensitive to this model. This article studies the lepton portal coupling as well as the scalar portal coupling (between S± and SM Higgs boson), as the latter is generally allowed in the Lagrangian. The inclusion of scalar portal coupling not only significantly enhances the LHC reach via the gg → h* → S+S− process, but also provides a few novel signal channels, such as the exotic decays and coupling devi- ations of the Higgs boson, offering new opportunities to probe the model. In addition, we also study the Drell-Yan production of S+S− at future lepton colliders, and find out that the scenario where one S± is off-shell can be used to measure the lepton portal coupling directly. In particular, we are interested in the possibility that the scalar potential triggers a first-order phase transition and hence provides the stochastic gravitational wave (GW) signals. In this case, the terrestrial collider experiments and space-based GW detectors serve as complementary approaches to probe the model.

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