Title: 

Nonthermal Heavy Dark Matter from a First-Order Phase Transition

https://inspirehep.net/literature/2765834

Abstract: 

We study nonthermal production of heavy dark matter from the dynamics of the background scalar field during a first-order phase transition, predominantly from bubble collisions. In scenarios where bubble walls achieve runaway behavior and get boosted to very high energies, we find that it is possible to produce dark matter with mass several orders of magnitude above the symmetry breaking scale or the highest temperature ever reached by the thermal plasma. We also demonstrate that the existing formalism for calculating particle production from bubble dynamics in a first-order phase transition is not gauge invariant, and can lead to spurious results. While a rigorous and complete resolution of this problem is still lacking, we provide a practical prescription for the computation that avoids unphysical contributions and should provide reliable order-of-magnitude estimates of this effect. Furthermore, we point out the importance of three-body decays of the background field excitations into scalars and gauge bosons, which provide the dominant contributions at energy scales above the scale of symmetry breaking. Using our improved results, we find that scalar, fermion, and vector dark matter are all viable across a large range of mass scales, from O(10) TeV to a few orders of magnitude below the Planck scale, and the corresponding phase transitions can be probed with current and future gravitational wave experiments.

Title: 

Geometric view for the pNGB potential

Abstract: 

We investigate the pseudo-Nambu-Goldstone bosons (pNGBs) potential in the geometrical point of view. In this talk, first I will review about spontaneous symmetry breaking and NGB and how to construct the effective Lagrangian. Then I will discuss about pNGB with explicit symmetry breaking and how to essentially organise or structurally understand the pNGB potential without recourse to the UV symmetries.

Title: 

Non-thermal WIMPy baryogenesis from early matter-dominated epoch

Abstract: 

 From satellite-based measurements, the Standard Model (SM) can explain only 5 percent of the energy density of the present Universe, and the baryon density at present infers the existence of baryon asymmetry of the Universe. About 26 percent of energy density consists of Dark Matter (DM), which plays a crucial role in large scale structure formations. 

 In new theoretical models beyond the SM, there are many long-lived massive particles that can dominate the energy density of the Universe, and eventually decay. And, the matter-antimatter asymmetry should be produced after Inflation since the initial abundance of baryon asymmetry is diluted during Inflation. 

If we consider the early matter-dominated epoch, dark matter can be non-thermally produced during a reheating period, and subsequently annihilate again to lighter SM particles even after the thermal freeze-out. We will discuss the possibility that re-annihilation of dark matter provides the correct baryon asymmetry and the observed relic abundance of DM. In my presentation, I will talk about both DM and baryon asymmetry production with low reheating temperature triggered by the decay of a long-lived massive particle or by evaporation of primordial black holes.

References:

https://arxiv.org/abs/1803.00820

https://arxiv.org/abs/2309.16122