Linear seesaw leptogenesis before/after electroweak symmetry breaking

Fuente: arXiv
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Main Authors: Shao, Yan, Zhao, Zhen-hua
Format: Preprint
Published: 2025
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author Shao, Yan
Zhao, Zhen-hua
author_facet Shao, Yan
Zhao, Zhen-hua
contents The linear seesaw (LSS) model provides a natural framework for generating small neutrino masses at low energy scales, thereby offering promising testability prospects. However, in generic LSS models, the exact mass degeneracy (before the electroweak symmetry breaking) between the two sterile neutrinos that form a Dirac pair precludes the generation of CP asymmetries from their interplay, posing a significant challenge to explaining the observed baryon (or lepton) asymmetry of the Universe via the leptogenesis mechanism. In this work, we explore two well-motivated approaches to generate a suitable mass splitting for the two sterile neutrinos that form a Dirac pair, and consequently naturally realize a resonantly enhanced generation of baryon (and lepton) asymmetry. First, we demonstrate that the renormalization group evolution effects can naturally induce the desired mass splitting for the sterile neutrinos, resulting in a successful generation of the observed baryon asymmetry of the Universe. Second, motivated by the recent result from the EMPRESS collaboration that indicates the possible existence of a large lepton asymmetry of the Universe, we explore the possibility that a large lepton asymmetry might naturally follow from the electroweak symmetry breaking which automatically induces the desired mass splitting for the sterile neutrinos.
format Preprint
id arxiv_https___arxiv_org_abs_2509_14524
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Linear seesaw leptogenesis before/after electroweak symmetry breaking
Shao, Yan
Zhao, Zhen-hua
High Energy Physics - Phenomenology
The linear seesaw (LSS) model provides a natural framework for generating small neutrino masses at low energy scales, thereby offering promising testability prospects. However, in generic LSS models, the exact mass degeneracy (before the electroweak symmetry breaking) between the two sterile neutrinos that form a Dirac pair precludes the generation of CP asymmetries from their interplay, posing a significant challenge to explaining the observed baryon (or lepton) asymmetry of the Universe via the leptogenesis mechanism. In this work, we explore two well-motivated approaches to generate a suitable mass splitting for the two sterile neutrinos that form a Dirac pair, and consequently naturally realize a resonantly enhanced generation of baryon (and lepton) asymmetry. First, we demonstrate that the renormalization group evolution effects can naturally induce the desired mass splitting for the sterile neutrinos, resulting in a successful generation of the observed baryon asymmetry of the Universe. Second, motivated by the recent result from the EMPRESS collaboration that indicates the possible existence of a large lepton asymmetry of the Universe, we explore the possibility that a large lepton asymmetry might naturally follow from the electroweak symmetry breaking which automatically induces the desired mass splitting for the sterile neutrinos.
title Linear seesaw leptogenesis before/after electroweak symmetry breaking
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2509.14524