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CP violation and circular polarisation in neutrino radiative decay

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

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Shyam Balaji

Maura Ramirez-Quezada

Ye-Ling Zhou


The radiative decay of neutral fermions has been studied for decades but CP violation induced within such a paradigm has evaded attention. CP violation in these processes can produce an asymmetry between circularly polarised directions of the radiated photons and produces an important source of net circular polarisation in particle and astroparticle physics observables. The results presented in this work outlines the general connection between CP violation and circular polarisation for both Dirac and Majorana fermions and can be used for any class of models that produce such radiative decays. The total CP violation is calculated based on a widely studied Yukawa interaction considered in both active and sterile neutrino radiative decay scenarios as well as searches for dark matter via direct detection and collider signatures. Finally, the phenomenological implications of the formalism on keV sterile neutrino decay, leptogenesis-induced right-handed neutrino radiative decay and IceCube-driven heavy dark matter decay are discussed.


Balaji, S., Ramirez-Quezada, M., & Zhou, Y. (2020). CP violation and circular polarisation in neutrino radiative decay. Journal of High Energy Physics, 2020(4), Article 178.

Journal Article Type Article
Acceptance Date Apr 5, 2020
Online Publication Date Apr 27, 2020
Publication Date Apr 30, 2020
Deposit Date May 7, 2020
Publicly Available Date Apr 27, 2021
Journal Journal of High Energy Physics
Print ISSN 1126-6708
Publisher Scuola Internazionale Superiore di Studi Avanzati (SISSA)
Peer Reviewed Peer Reviewed
Volume 2020
Issue 4
Article Number 178


Accepted Journal Article (704 Kb)

Copyright Statement
This is a post-peer-review, pre-copyedit version of an article published in Journal of high energy physics. The final authenticated version is available online at:

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