Lepton asymmetry in S3 extended Standard Model

Mishra, Subhasmita and Giri, Anjan Kumar (2017) Lepton asymmetry in S3 extended Standard Model. In: The 15th International Conference on Flavor Physics CP Violation, June 5-9, 2017, Prague, Czech Republic.

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Abstract

Standard model (SM) of electroweak interaction seems to be complete and consistent with almost all the data obtained so far, nevertheless, some deviations in the B sector are observed apart from the neutrino oscillation. It is believed that the SM is not a complete theory as we cannot explain the matter-antimatter asymmetry in our Universe in addition to the fact that the visible Universe contains just 5% of the total energy budget. We consider leptogenesis in a minimal S 3 extended standard model with a Higgs doublet and 3 right handed singlet Majorana neutrinos. We studied the neutrino phenomenology from the flavor structure of the S 3 invariant mass matrix in com- patible with the 1 σ experimental oscillation parameters.We have chosen the out of equilibrium decays of the lightest right handed Majorana neutrino to be in the temeperature range less than 10 8 GeV, where one flavor approximation isn’t valid as all the charged lepton yukawa couplings are in equilibrium. Hence we can distinguish between the τ and other lepton flavors. Thereafter, we generate the lepton asymmetry by adding flavor effects coming individually from all the lep- tons sector. This flavor approximation can generate an appreciable lepton asymmetry which can convert to the baryon asymmetry through sphaleron process and can account for the experimental observation. Imposition of S 3 flavor structure of the yukawa couplings restrict the asymmetry in the τ sector to vanish whereas the asymmetries in other leptons sector remain finite.

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