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Main Authors: Hamada, Yu, Nakano, Wakutaka
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2405.09599
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author Hamada, Yu
Nakano, Wakutaka
author_facet Hamada, Yu
Nakano, Wakutaka
contents We analytically calculate the spectrum of stochastic gravitational waves (GWs) emitted by expanding string loops on domain walls in the scenario where domain walls decay by nucleation of string loops. By introducing macroscopic parameters characterizing the nucleation of the loops, the stochastic GW spectrum is derived in a way that is independent of the details of particle physics models. In contrast to GWs emitted from bubble collisions of the false vacuum decay, the string loops do radiate GWs even when they are perfectly circular before their collisions, resulting in that more and more contribution to the spectrum comes from the smaller and smaller loops compared to the typical size of the collided loops. Consequently, the spectrum is linearly proportional to the frequency at the high-frequency region, which is peculiar to this GW source. Furthermore, the results are compared with the recent nano-Hertz pulsar timing array signal, as well as the projected sensitivity curves of future gravitational wave observatories.
format Preprint
id arxiv_https___arxiv_org_abs_2405_09599
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Gravitational wave spectrum from expanding string loops on domain walls: Implication for nanohertz pulsar timing array signal
Hamada, Yu
Nakano, Wakutaka
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
We analytically calculate the spectrum of stochastic gravitational waves (GWs) emitted by expanding string loops on domain walls in the scenario where domain walls decay by nucleation of string loops. By introducing macroscopic parameters characterizing the nucleation of the loops, the stochastic GW spectrum is derived in a way that is independent of the details of particle physics models. In contrast to GWs emitted from bubble collisions of the false vacuum decay, the string loops do radiate GWs even when they are perfectly circular before their collisions, resulting in that more and more contribution to the spectrum comes from the smaller and smaller loops compared to the typical size of the collided loops. Consequently, the spectrum is linearly proportional to the frequency at the high-frequency region, which is peculiar to this GW source. Furthermore, the results are compared with the recent nano-Hertz pulsar timing array signal, as well as the projected sensitivity curves of future gravitational wave observatories.
title Gravitational wave spectrum from expanding string loops on domain walls: Implication for nanohertz pulsar timing array signal
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2405.09599