Abstract
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 N1 and N2. 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 N2→ N1γ 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.
Highlights
JHEP12(2020)090 eigenstates can trigger a heavier neutrino radiatively decaying to a lighter neutrino through the release of a photon
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
A full one-loop calculation of the transition dipole moment is performed in the context of the Standard Model with an arbitrary number of right-handed singlet neutrinos
Summary
We give a brief review of the framework for CP violation in neutrino radiative decays. We refer to our former paper ref. [38] for the detailed derivation.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have