Flavor effects in Leptogenesis

por Enrico Nardi (INFN Laboratori Nazionali di Frascati - Rome, Italy and Instituto de Fisica, Universidad de Antioquia - Medellin, Colombia)

miércoles 22 feb. 2006 12:30 → 13:30 Europe/Madrid

Sala Seminarios IFIC (Edf. Institutos de Investigación)

If leptogenesis occurs in the medium (low) temperature regime $T\lsim 10^{12}$ GeV ($\lsim 10^{9}\,$ GeV) where the rates of processes mediated by the $\tau$ (and $\mu$) Yukawa coupling are non negligible, lepton flavors dynamics can have surprising effects on the generation of cosmic asymmetries: (i) The baryon asymmetry can be enhanced by up to one order of magnitude; (ii) The sign of the asymmetry can be opposite to what one would predict from the sign of the total lepton asymmetry $\epsilon_1$; (iii) Successful leptogenesis is possible even when the total lepton asymmetry in the heavy neutrinos decays vanishes ($\epsilon_1=0$). We discuss these effects, and we also comment on additional corrections from Higgs effects and sphalerons processes.