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Main Authors: D'Eramo, Francesco, Tesi, Andrea, Vaskonen, Ville
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2407.19997
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author D'Eramo, Francesco
Tesi, Andrea
Vaskonen, Ville
author_facet D'Eramo, Francesco
Tesi, Andrea
Vaskonen, Ville
contents We explore the irreducible cosmological implications of a singlet real scalar field. Our focus is on theories with an approximate and spontaneously broken $\mathbb{Z}_2$ symmetry where quasi-stable domain walls can form at early times. This seemingly simple framework bears a wealth of phenomenological implications that can be tackled by means of different cosmological and astrophysical probes. We elucidate the connection between domain wall dynamics and the production of dark matter and gravitational waves. In particular, we identify three main benchmark scenarios. The gravitational wave signal observed by pulsar timing arrays can be generated by the domain walls if the mass of the singlet is $m_s \sim\,$PeV. For lower masses, but with $m_s \gtrsim 10\,$GeV, scalars produced in the annihilation of the domain walls can be dark matter with a distinctive feature in their power spectrum. Finally, the thermal bath provides an unavoidable source of unstable scalars via the freeze-in mechanism whose subsequent decays can be tested by their imprints on cosmological and terrestrial observables.
format Preprint
id arxiv_https___arxiv_org_abs_2407_19997
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Irreducible cosmological backgrounds of a real scalar with a broken symmetry
D'Eramo, Francesco
Tesi, Andrea
Vaskonen, Ville
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
We explore the irreducible cosmological implications of a singlet real scalar field. Our focus is on theories with an approximate and spontaneously broken $\mathbb{Z}_2$ symmetry where quasi-stable domain walls can form at early times. This seemingly simple framework bears a wealth of phenomenological implications that can be tackled by means of different cosmological and astrophysical probes. We elucidate the connection between domain wall dynamics and the production of dark matter and gravitational waves. In particular, we identify three main benchmark scenarios. The gravitational wave signal observed by pulsar timing arrays can be generated by the domain walls if the mass of the singlet is $m_s \sim\,$PeV. For lower masses, but with $m_s \gtrsim 10\,$GeV, scalars produced in the annihilation of the domain walls can be dark matter with a distinctive feature in their power spectrum. Finally, the thermal bath provides an unavoidable source of unstable scalars via the freeze-in mechanism whose subsequent decays can be tested by their imprints on cosmological and terrestrial observables.
title Irreducible cosmological backgrounds of a real scalar with a broken symmetry
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2407.19997