We argue that a nonthermal leptogenesis occurs spontaneously, without direct couplings of the inflaton with right-handed neutrinos, in a wide class of high-scale inflation models such as the chaotic and hybrid inflation. It is only a finite vacuum expectation value of the inflaton, or more precisely, a linear term in the Kähler potential, that is a prerequisite for the spontaneous nonthermal leptogenesis. To exemplify how it works, we show that a chaotic inflation model in supergravity naturally produces a right amount of baryon asymmetry via the spontaneous nonthermal leptogenesis. We also discuss the gravitino production from the inflaton.

• Received 15 November 2006

DOI:https://doi.org/10.1103/PhysRevD.74.123523