|講演タイトル||Leptogenesis during Axion Relaxation after Inflation|
|講演者||Dr. Kai Schmitz (IPMU)|
In this talk, I present a novel and minimal alternative to thermal leptogenesis, which builds upon the assumption that the electroweak gauge bosons are coupled to an axion-like scalar field, as it is, for instance, the case in certain string compactifications. The motion of this axion-like field after the end of inflation generates an effective chemical potential for leptons and antileptons, which, in the presence of lepton number-violating scatterings mediated by heavy Majorana neutrinos, provides an opportunity for baryogenesis via leptogenesis. In contrast to thermal leptogenesis, the final baryon asymmetry turns out to be insensitive to the masses and CP-violating phases in the heavy neutrino sector. Moreover, the proposed scenario requires a reheating temperature of at least O(10^12) GeV and it is, in particular, consistent with heavy neutrino masses close the scale of grand unification. This talk is based on recent work (Phys. Rev. Lett. 115 (2015) 1, 011302, 1412.2043 [hep-ph]) in collaboration with Alexander Kusenko from UCLA and Tsutomu T. Yanagida from Kavli IPMU."