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Main Authors: Kanemura, Shinya, Li, Shao-Ping
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2509.03905
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author Kanemura, Shinya
Li, Shao-Ping
author_facet Kanemura, Shinya
Li, Shao-Ping
contents Particle decay in leptogenesis provides a simple avenue to explain the baryon asymmetric universe, where the decaying particle can provide the out-of-equilibrium condition to create a net lepton asymmetry. It is widely anticipated that the lepton asymmetry would be changed significantly by varying couplings and the decaying particle mass, especially in the weak washout regime. Contrary to this naive expectation, we demonstrate a general phenomenon in a class of leptogenesis scenarios from heavy particle decay, where varying the mass and couplings would not modify the lepton asymmetry in a noticeable way, as these mass and coupling effects are largely canceled out from the evolution of the decaying particle. It points out that a much broader parameter space in the mass and couplings will open automatically once leptogenesis is realized in a benchmark point; however, tuning the mass and couplings to boost leptogenesis will be challenging.
format Preprint
id arxiv_https___arxiv_org_abs_2509_03905
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The mass-coupling effect in leptogenesis
Kanemura, Shinya
Li, Shao-Ping
High Energy Physics - Phenomenology
Particle decay in leptogenesis provides a simple avenue to explain the baryon asymmetric universe, where the decaying particle can provide the out-of-equilibrium condition to create a net lepton asymmetry. It is widely anticipated that the lepton asymmetry would be changed significantly by varying couplings and the decaying particle mass, especially in the weak washout regime. Contrary to this naive expectation, we demonstrate a general phenomenon in a class of leptogenesis scenarios from heavy particle decay, where varying the mass and couplings would not modify the lepton asymmetry in a noticeable way, as these mass and coupling effects are largely canceled out from the evolution of the decaying particle. It points out that a much broader parameter space in the mass and couplings will open automatically once leptogenesis is realized in a benchmark point; however, tuning the mass and couplings to boost leptogenesis will be challenging.
title The mass-coupling effect in leptogenesis
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2509.03905