Speaker
Hisashi Okui
(Niigata University)
Description
Right-handed neutrinos are particles beyond the SM introduced in the seesaw mechanism that can explain tiny neutrino masses. We revisit the entropy production from the decay of right-handed neutrinos with the GeV scale masses. This additional production of entropy dilutes the DM and baryon abundances. Furthermore, we estimate the effect on the primordial gravitational wave spectrum. Primordial gravitational waves are closely related to the thermal history of the universe. Therefore, the modified history by right-handed neutrino is imprinted in the gravitational wave spectrum. We then evaluate the influence on the spectrum and the sensitivity in future experiments.
