Anarchy and Leptogenesis

Abstract

We study if leptogenesis works successfully together with the neutrino mass anarchy hypothesis. We find that the predicted neutrino mass spectrum is sensitive to the reheating temperature or the inflaton mass, while the distributions of the neutrino mixing angles and CP violation phases remain intact as determined by the invariant Haar measure of U(3). In the case of thermal leptogenesis, the light neutrino mass distribution agrees well with the observations if the reheating temperature is O(10^{9-11}) GeV. The mass spectrum of the right-handed neutrinos and the neutrino Yukawa matrix exhibit a certain pattern, as a result of the competition between random matrices with elements of order unity and the wash-out effect. Non-thermal leptogenesis is consistent with observation only if the inflaton mass is larger than or comparable to the typical right-handed neutrino mass scale. Cosmological implications are discussed in connection with the 125GeV Higgs boson mass.