(Slide attached)
* Title: Spontaneous leptogenesis via Majoron oscillation
* Speaker: Kunio Kaneta (CTPU) (at KAIST Munji Campus)
* Date: 12:00-1:00 PM, 2 Oct 2015
* Abstract: Although cosmological and astrophysical observations have found the baryon asymmetry of the universe, the standard model of particle physics hardly explain its origin, and thus new physics beyond the standard model is required. Leptogenesis is one of convincing explanations for baryogenesis, in which tiny neutrino masses can be explained by the presence of right-handed Majorana neutrinos via the seesaw mechanism. There, Majorana masses of the right-handed neutrinos would be originated from a spontaneous breakdown of $B-L$ symmetry, which can lead to a Nambu-Goldstone boson called Majoron. We discuss a possibility that leptogenesis takes place in the primordial thermal bath due to the background Majoron field in motion.
* References: Phys.Rev. D92 (2015) 3, 035019