Journal Article

CP violation in neutral lepton transition dipole moment

Ramirez-Quezada, Maura, Balaji, Shyam, Zhou, Ye-Ling

2020

Overview

A bstract The CP violation in the neutrino transition electromagnetic dipole moment is discussed in the context of the Standard Model with an arbitrary number of right-handed singlet neutrinos. A full one-loop calculation of the neutrino electromagnetic form factors is performed in the Feynman gauge. A non-zero CP asymmetry is generated by a required threshold condition for the neutrino masses along with non-vanishing CP violating phases in the lepton flavour mixing matrix. We follow the paradiagm of CP violation in neutrino oscillations to parametrise the flavour mixing contribution into a series of Jarlskog-like parameters. This formalism is then applied to a minimal seesaw model with two heavy right-handed neutrinos denoted N 1 and N 2 . We observe that the CP asymmetries for decays into light neutrinos N → νγ are extremely suppressed, maximally around 10 − 17 . However the CP asymmetry for N 2 → N 1 γ can reach of order unity. Even if the Dirac CP phase δ is the only source of CP violation, a large CP asymmetry around 10 − 5 –10 − 3 is comfortably achieved.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V,SpringerOpen
• Subject: Asymmetry / Classical and Quantum Gravitation / CP violation / Dipole moments / Elementary Particles / Flavor (particle physics) / Form factors / High energy physics / Leptons / Matter & antimatter / Neutrino Physics / Neutrinos / Physics / Physics and Astronomy / Quantum Field Theories / Quantum Field Theory / Quantum Physics / Regular Article - Theoretical Physics / Relativity Theory / String Theory