Leptogenesis in the seesaw models

• Grant number: 22/10511-1
• Support Opportunities: Scholarships in Brazil - Master
• Start date: December 01, 2022
• End date: August 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Physics - Elementary Particle Physics and Fields
• Principal Investigator: Chee Sheng Fong
• Grantee: Gabriel de Oliveira Aragão
• Host Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil
• Associated research grant: 19/11197-6 - Precision test of baryogenesis, AP.JP

Abstract

Treating the Standard Model (SM) as an effective field theory, small Majorana neutrino mass arises from the unique mass dimension five operator known as the Weinberg operator. This operator breaks lepton number by two units and opens up the possibility of baryogenesis through leptogenesis at high scale. There are only three tree-level ultraviolet completions of the Weinberg operator, known respectively as type-I, type-II and type-III seesaw models. In these models, lepton asymmetry is generated through the slow decays of heavy fermions (type-I and type-III) or scalars (type-II). While the heavy fermions in type-I seesaw model carry no SM gauge charge, the heavy scalars and fermions respectively in type-II and III seesaw models carry the SM weak charge and experience gauge interactions. These interactions can have large effect on leptogenesis.