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Main Authors: Deppisch, Frank F., Gonzalo, Tomás E., Majumdar, Chayan, Zhang, Zhong
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2410.06970
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author Deppisch, Frank F.
Gonzalo, Tomás E.
Majumdar, Chayan
Zhang, Zhong
author_facet Deppisch, Frank F.
Gonzalo, Tomás E.
Majumdar, Chayan
Zhang, Zhong
contents Heavy neutral leptons (HNLs) are constrained by requirements of Big Bang Nucleosynthesis (BBN) as their decays significantly impact the formation of the primordial elements. We propose here a model where the primary decay channel for the HNLs is to an axion-like particle (ALP) and a neutrino. Consequently, HNLs can decay earlier and evade the BBN bound for lower masses, provided the ALPs themselves decay considerably later. Further cosmological and astrophysical constraints limit severely the range of validity of the ALP properties. We find that a new parameter region opens up for HNLs with masses between 1 MeV and 1 GeV, and active-sterile neutrino mixing strengths between $10^{-9}$ and $10^{-6}$ that is consistent with constraints and can be probed in future searches. In such a scenario, current bounds as well as sensitivities of future direct HNL searches such as at NA62 and DUNE will be affected.
format Preprint
id arxiv_https___arxiv_org_abs_2410_06970
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Relaxing Limits from Big Bang Nucleosynthesis on Heavy Neutral Leptons with Axion-like Particles
Deppisch, Frank F.
Gonzalo, Tomás E.
Majumdar, Chayan
Zhang, Zhong
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
Heavy neutral leptons (HNLs) are constrained by requirements of Big Bang Nucleosynthesis (BBN) as their decays significantly impact the formation of the primordial elements. We propose here a model where the primary decay channel for the HNLs is to an axion-like particle (ALP) and a neutrino. Consequently, HNLs can decay earlier and evade the BBN bound for lower masses, provided the ALPs themselves decay considerably later. Further cosmological and astrophysical constraints limit severely the range of validity of the ALP properties. We find that a new parameter region opens up for HNLs with masses between 1 MeV and 1 GeV, and active-sterile neutrino mixing strengths between $10^{-9}$ and $10^{-6}$ that is consistent with constraints and can be probed in future searches. In such a scenario, current bounds as well as sensitivities of future direct HNL searches such as at NA62 and DUNE will be affected.
title Relaxing Limits from Big Bang Nucleosynthesis on Heavy Neutral Leptons with Axion-like Particles
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2410.06970