Transient domain walls and lepton asymmetry in the left-right symmetric model

Abstract

It is shown that the dynamics of domain walls in left-right symmetric models, separating respective regions of unbroken SU(2) L and SU(2) R in the early universe, can give rise to baryogenesis via leptogenesis. Neutrinos have a spatially varying complex mass matrix due to CP-violating scalar condensates in the domain wall. The motion of the wall through the plasma generates a flux of lepton number across the wall which is converted to a lepton asymmetry by helicity-flipping scatterings. Subsequent processing of the lepton excess by sphalerons results in the observed baryon asymmetry, for a range of parameters in left-right symmetric models.

GaugedB−Lsymmetry and baryogenesis via leptogenesis at TeV scale

“…We discuss qualitatively the possibility of lepton asymmetry during the left-right symmetry breaking phase transition [24]. In the following we recapitulate the important aspects of left-right symmetric model for our purpose and the possible non-thermal mechanism of producing raw lepton asymmetry.…”

“…It was shown in [24] that within the thickness of the domain walls the net CP violating phase becomes position dependent. Under these circumstances a formalism exists [37,38,39], wherein the chemical potential µ L created for the Lepton number can be computed as a solution of the diffusion equation…”

“…After integration of the above equation and using inputs from the numerical solutions we find the raw lepton asymmetry [24] η raw…”

“…In [23,24] it was shown that the Left-Right symmetric model [25,26] presents just such a possibility. In this model B − L appears as a gauged symmetry in a natural way.…”

Gauge mediated supersymmetry breaking and the cosmology of the left-right symmetric model

“…This mechanism is analogous to that explored for the electroweak baryogenesis [37], provided a source for CP asymmetry can be found. It has been shown [38] that the domain walls occurring in models such as to be studied in this paper generically…”