Annihilogenesis

Abstract

We investigate a novel interplay between the decay and annihilation of a particle whose mass undergoes a large shift during a first order phase transition, leading to the particles becoming trapped in the false vacuum and enhancing their annihilation rates as the bubbles of true vacuum expand. This opens up a large region of the parameter space where annihilations can be important. We apply this scenario to baryogenesis, where we find that annihilations can be enhanced enough to generate the required baryon asymmetry even for relatively tiny annihilation cross sections with modest CP asymmetries.

Leptogenesis triggered by a first-order phase transition

“…2 One might concern that in case of M 1 /T p 1 the RHNs do not have sufficient energy to cross the wall, as the average kinetic energy of ν R is O(T p ). Were that true, most of the RHNs will be trapped in the old vacuum [27][28][29][30][31], and only a tiny fraction of them can be "filtered" to the new vacuum [32][33][34][35], resulting in a much suppressed ν R number density in the φ = 0 phase, and the resultant BAU is also negligible, as pointed out in [26,36]. This issue, however, can be solved, provided that the bubbles are expanding in an ultrarelativistic velocity, i.e.…”

First-order phase transition and fate of false vacuum remnants

“…See refs [52][53][54]. for other baryogenesis and dark matter mechanisms involving particle trapping, and refs [55][56][57][58][59][60][61][62][63][64][65].…”

Pinning down the primordial black hole formation mechanism with gamma-rays and gravitational waves

“…However, for the false vacuum remnants to be sufficiently dense to collapse into PBHs, we have to address an important issue: how to prevent the trapped fermions from disappearing through χ χ → φ, φφ, etc, and eventually to the SM particles in the thermal bath? Such annihilations are inevitably enhanced when the remnants shrink, reducing the fermion number density greatly [165,166] and consequently destroying any possibility of collapse into PBHs. To have PBHs formed, there are two typical scenarios: I.…”