New aspects of leptogenesis bounds

Understand

We present a general analysis that reveals new aspects of the leptogenesis bounds on neutrino masses and on the reheat temperature of the Universe.

• After revisiting a known effect coming from an unbounded term in the total CP asymmetry, we show that an unbounded term in the flavored CP asymmetries has a stronger impact.
• It relaxes the lower bound on the reheat temperature down to 10^8 GeV for (M_2-M_1)/M_1=O(1-100) and for a mild tuning of the parameters in the see-saw orthogonal matrix.
• We also consider the effect of the Higgs asymmetry, showing that it lowers the upper bound on the neutrino masses in the so-called fully flavored regime where classic Boltzmann equations can be used.