  In leptogenesis scenario, the decays of heavy Majorana neutrinos generate
lepton family asymmetries, $Y_e, Y_{\mu}$ and $Y_{\tau}$. They are sensitive to
CP violating phases in seesaw models. The time evolution of the lepton family
asymmetries are derived by solving Boltzmann equations. By taking a minimal
seesaw model, we show how each family asymmetry varies with a CP violating
phase. For instance, we find the case that the lepton asymmetry is dominated by
$Y_{\mu}$ or $Y_{\tau}$ depending on the choice of the CP violating phase. We
also find the case that the signs of lepton family asymmetries $Y_{\mu}$ and
$Y_{\tau}$ are opposite each other. Their absolute values can be larger than
the total lepton asymmetry and the baryon asymmetry may result from the
cancellation of the lepton family asymmetries.

High Energy Physics - Phenomenology