Abstract
We present a novel mechanism which leads to the baryon asymmetry generation during the strong first order phase transition. If the bubble wall propagates with ultra-relativistic velocity, it has been shown [1] that it can produce states much heavier than the scale of the transition and that those states are then out of equilibrium. In this paper, we show that this production mechanism can also induce CP-violation at one-loop level. We calculate those CP violating effects during the heavy particle production and show, that combined with baryon number violating interactions, those can lead to successful baryogenesis. Two models based on this mechanism are constructed and their phenomenology is discussed. Stochastic gravitational wave signals turn out to be generic signatures of this type of models.
Highlights
Though this ratio is much smaller than unity, it calls for an explanation in terms of early universe dynamics, i.e. baryogenesis
We present a novel mechanism which leads to the baryon asymmetry generation during the strong first order phase transition
One interesting possibility for the fulfillment of the out-of-equilibrium process requirement is a scenario in which a first order phase transition (FOPT) occurs in the early history of the universe and this will be the focus of the study in the present paper
Summary
Let us start by reviewing the process of heavy states production during the phase transition presented in [1]. We can see that there will be an efficient production of the heavy states, which will not be Boltzmann suppressed, the Lorentz boost factor γw for the wall expansion needs to be large enough After this warm-up exercise we can proceed to the calculation of the one loop effects. The momentum is not conserved only in the vertex with the φ insertion, the energy and x − y momentum conservation still fixes the value of the loss of the z component of momentum At this point since φ is a scalar (no polarization vectors are needed) the matrix element is exactly the same as for the process χ(k) → N (q)φ(∆pz) and can be calculated using the usual Lorentz invariant Feynman diagram techniques
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