Leptogenesis via varying Weinberg operator: the Closed-Time-Path approach

• Published in: The journal of high energy physics Vol. 2020; no. 1; pp. 22 - 49
• Main Authors: Turner, Jessica, Zhou, Ye-Ling
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2020; Springer Nature B.V; Springer Berlin; SpringerOpen
• Subjects: Asymmetry; Baryons; Cosmology; Cosmology of Theories Beyond the SM; CP Violation; Field theory; High energy physics; Leptons; Mathematical analysis; Neutrino Physics; Phase transitions; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Quantum field theory; Quantum theory; Regular Article - Theoretical Physics; Relativity; Scalars; Spacetime; Temperature effects; Thermal Field Theory; Cosmology of Theories beyond the SM; Neutrino Physics; CP violation; Thermal Field Theory
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP01(2020)022

A bstract In this work we provide a detailed study of the CP violating phase transition (CPPT) which is a new mechanism proposed to produce a baryon asymmetry. This mechanism exploits the Weinberg operator whose coefficient is dynamically realised from the vacuum expectation values (VEVs) of new scalars. In the specific case of the first order phase transition, the scalar VEVs vary in the bubble wall which separates the two phases. This results in a spacetime varying coefficient for the Weinberg operator. The interference of two Weinberg operators at different spacetime points generates a CP asymmetry between lepton and anti-lepton production/annihilation processes, which eventually results in an asymmetry between baryon and anti-baryon number densities in the early Universe. We present the calculation of the lepton asymmetry, based on non-equilibrium quantum field theory methods, in full. We consider the influence of the bubble wall characteristics and the impact of thermal effects on the lepton asymmetry and draw a comparison between the CPPT mechanism and electroweak baryogenesis.