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arXiv · 2401.00687

Constraining MeV to 10 GeV majoron by Big Bang Nucleosynthesis

Abstract

We estimate the Big Bang nucleosynthesis (BBN) constraint on the majoron in the mass range between $1\,{\rm MeV}$ to $10\,{\rm GeV}$ which dominantly decays into the standard model neutrinos. When the majoron lifetime is shorter than $1\,{\rm sec}$, the injected neutrinos mainly heat up background plasma, which alters the relation between photon temperature and background neutrino temperature. For a lifetime longer than $1\,{\rm sec}$, most of the injected neutrinos directly contribute to the protons-to-neutrons conversion. In both cases, deuterium and helium abundances are enhanced, while the constraint from the deuterium is stronger than that from the helium. $^7{\rm Li}$ abundance gets decreased as a consequence of additional neutrons, but the parameter range that fits the observed $^7{\rm Li}$ abundance is excluded by the deuterium constraint. We also estimate other cosmological constraints and compare them with the BBN bound.

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Sanghyeon Chang, Sougata Ganguly, Tae Hyun Jung, Tae-Sun Park, Chang Sub Shin. 2024-01-01. Constraining MeV to 10 GeV majoron by Big Bang Nucleosynthesis. https://arxiv.org/abs/2401.00687

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