More relaxed supersymmetric electroweak baryogenesis

Abstract

We reanalyze the issue of generation of the baryon asymmetry at the electroweak phase transition in the MSSM and compute the baryon asymmetry assuming the presence of non-trivial CP-violating phases in the parameters associated with the left-right stop mixing term and the Higgsino mass $\mu$. Making use of the closed time-path (CTP) formalism of nonequilibrium field theory, we write down a set of quantum Boltzmann equations describing the local number density asymmetries of the particles involved in supersymmetric electroweak baryogenesis. CP-violating sources manifest ``memory'' effects which are typical of the quantum transport theory and are not present in the classical approach. Compared to previous estimates, these non-Markovian features enhance the final baryon asymmetry by at least two orders of magnitude. This means that a CP-violating phase $|\sin \phi_{\mu}|$ as small as $10^{-3}$ (or even smaller) is enough to generate the observed baryon asymmetry.