TY - JOUR

T1 - CP asymmetry in heavy Majorana neutrino decays at finite temperature

T2 - the hierarchical case

AU - Biondini, S.

AU - Brambilla, N.

AU - Vairo, A.

N1 - Publisher Copyright:
© 2016, The Author(s).

PY - 2016/9/1

Y1 - 2016/9/1

N2 - We consider the simplest realization of leptogenesis with one heavy Majorana neutrino species much lighter than the other ones. In this scenario, when the temperature of the early universe is smaller than the lightest Majorana neutrino mass, we compute at first order in the Standard Model couplings and, for each coupling, at leading order in the termperature the CP asymmetry in the decays of the lightest neutrino into leptons and anti-leptons. We perform the calculation using a hierarchy of two effective field theories organized as expansions in the inverse of the heavy-neutrino masses. In the ultimate effective field theory, leading thermal corrections proportional to the Higgs self coupling and the gauge couplings are encoded in one single operator of dimension five, whereas corrections proportional to the top Yukawa coupling are encoded in four operators of dimension seven, which we compute.

AB - We consider the simplest realization of leptogenesis with one heavy Majorana neutrino species much lighter than the other ones. In this scenario, when the temperature of the early universe is smaller than the lightest Majorana neutrino mass, we compute at first order in the Standard Model couplings and, for each coupling, at leading order in the termperature the CP asymmetry in the decays of the lightest neutrino into leptons and anti-leptons. We perform the calculation using a hierarchy of two effective field theories organized as expansions in the inverse of the heavy-neutrino masses. In the ultimate effective field theory, leading thermal corrections proportional to the Higgs self coupling and the gauge couplings are encoded in one single operator of dimension five, whereas corrections proportional to the top Yukawa coupling are encoded in four operators of dimension seven, which we compute.

KW - Beyond Standard Model

KW - Effective field theories

KW - Thermal Field Theory

UR - http://www.scopus.com/inward/record.url?scp=84988650885&partnerID=8YFLogxK

U2 - 10.1007/JHEP09(2016)126

DO - 10.1007/JHEP09(2016)126

M3 - Article

AN - SCOPUS:84988650885

SN - 1126-6708

VL - 2016

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 9

M1 - 126

ER -