Electromagnetic leptogenesis with light-heavy sterile neutrinos

We propose a novel leptogenesis scenario utilising the two-body decay of heavy right handed neutrino (RHN) via the electromagnetic dipole operator. While the requirement of the standard model (SM) gauge invariance requires such dipole operator only at dimension-6 forcing the generation of non-zero C...

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Main Authors: Debasish Borah, Arnab Dasgupta
Format: Article
Language:English
Published: Elsevier 2025-07-01
Series:Physics Letters B
Online Access:http://www.sciencedirect.com/science/article/pii/S0370269325003181
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author Debasish Borah
Arnab Dasgupta
author_facet Debasish Borah
Arnab Dasgupta
author_sort Debasish Borah
collection DOAJ
description We propose a novel leptogenesis scenario utilising the two-body decay of heavy right handed neutrino (RHN) via the electromagnetic dipole operator. While the requirement of the standard model (SM) gauge invariance requires such dipole operator only at dimension-6 forcing the generation of non-zero CP asymmetry from three-body decay with two-loop corrections, we write down dimension-5 dipole operators involving heavy RHN NR and its lighter counterpart νR. This allows the generation of lepton asymmetry in νR from two-body decay of heavy RHN which later gets transferred to left handed leptons via sizeable Yukawa coupling with a neutrinophilic Higgs doublet. The asymmetry in left handed leptons is then converted to baryon asymmetry via electroweak sphalerons. The lepton number violation by heavy RHN also induces a one-loop Majorana mass of νR rendering the light neutrinos to be Majorana fermions. While smallness of the Majorana mass of νR prevents additional sources or washout of lepton asymmetry, it also constrains the scale of leptogenesis. Sub-GeV sterile neutrinos, depending upon their masses come with interesting implications for low energy experiments, neutrino oscillation, warm dark matter as well as effective relativistic degrees of freedom. Additionally, heavy RHN can lead to observable monochromatic photon signatures at terrestrial experiments.
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spelling doaj-art-075da511f3a14175a5f826c167d94d452025-08-20T01:50:57ZengElsevierPhysics Letters B0370-26932025-07-0186613955710.1016/j.physletb.2025.139557Electromagnetic leptogenesis with light-heavy sterile neutrinosDebasish Borah0Arnab Dasgupta1Department of Physics, Indian Institute of Technology Guwahati, Assam 781039, India; Pittsburgh Particle Physics, Astrophysics, and Cosmology Center, Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA; Corresponding author.Pittsburgh Particle Physics, Astrophysics, and Cosmology Center, Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USAWe propose a novel leptogenesis scenario utilising the two-body decay of heavy right handed neutrino (RHN) via the electromagnetic dipole operator. While the requirement of the standard model (SM) gauge invariance requires such dipole operator only at dimension-6 forcing the generation of non-zero CP asymmetry from three-body decay with two-loop corrections, we write down dimension-5 dipole operators involving heavy RHN NR and its lighter counterpart νR. This allows the generation of lepton asymmetry in νR from two-body decay of heavy RHN which later gets transferred to left handed leptons via sizeable Yukawa coupling with a neutrinophilic Higgs doublet. The asymmetry in left handed leptons is then converted to baryon asymmetry via electroweak sphalerons. The lepton number violation by heavy RHN also induces a one-loop Majorana mass of νR rendering the light neutrinos to be Majorana fermions. While smallness of the Majorana mass of νR prevents additional sources or washout of lepton asymmetry, it also constrains the scale of leptogenesis. Sub-GeV sterile neutrinos, depending upon their masses come with interesting implications for low energy experiments, neutrino oscillation, warm dark matter as well as effective relativistic degrees of freedom. Additionally, heavy RHN can lead to observable monochromatic photon signatures at terrestrial experiments.http://www.sciencedirect.com/science/article/pii/S0370269325003181
spellingShingle Debasish Borah
Arnab Dasgupta
Electromagnetic leptogenesis with light-heavy sterile neutrinos
Physics Letters B
title Electromagnetic leptogenesis with light-heavy sterile neutrinos
title_full Electromagnetic leptogenesis with light-heavy sterile neutrinos
title_fullStr Electromagnetic leptogenesis with light-heavy sterile neutrinos
title_full_unstemmed Electromagnetic leptogenesis with light-heavy sterile neutrinos
title_short Electromagnetic leptogenesis with light-heavy sterile neutrinos
title_sort electromagnetic leptogenesis with light heavy sterile neutrinos
url http://www.sciencedirect.com/science/article/pii/S0370269325003181
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