New Massless Spectra from Cosmic String Cusps

Fuente: arXiv
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Main Authors: Drew, Amelia, Rybak, Ivan
Format: Preprint
Published: 2025
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author Drew, Amelia
Rybak, Ivan
author_facet Drew, Amelia
Rybak, Ivan
contents In the standard picture of cosmic strings, cusps are generic features of Nambu-Goto loops where the string momentarily reaches the speed of light. They have a characteristic sharp profile, following $y \sim x^{2/3}$ in the $(x,y)$ plane, and produce strong gravitational-wave (GW) bursts with frequency-domain strain $\mathop{\tilde{\!κ}}(ω) \propto ω^{-4/3}$, making them key targets for current and future GW searches. However, under certain conditions, this generic picture can differ. We identify cusp solutions with different, including smooth, shapes, and compute their massless GW and axion spectra. We derive a general expression for all possible Nambu-Goto cusp spectra with the asymptotic form $\mathop{\tilde{\!κ}}(ω) \propto ω^{-n/(2n-1)} ω^{-m/(2m-1)}$ where $n, m\geq 2$. We investigate the effect of realistic corrections to the Nambu-Goto description, such as those from backreaction and finite string width, which introduce a high frequency cutoff.
format Preprint
id arxiv_https___arxiv_org_abs_2512_12258
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle New Massless Spectra from Cosmic String Cusps
Drew, Amelia
Rybak, Ivan
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Theory
In the standard picture of cosmic strings, cusps are generic features of Nambu-Goto loops where the string momentarily reaches the speed of light. They have a characteristic sharp profile, following $y \sim x^{2/3}$ in the $(x,y)$ plane, and produce strong gravitational-wave (GW) bursts with frequency-domain strain $\mathop{\tilde{\!κ}}(ω) \propto ω^{-4/3}$, making them key targets for current and future GW searches. However, under certain conditions, this generic picture can differ. We identify cusp solutions with different, including smooth, shapes, and compute their massless GW and axion spectra. We derive a general expression for all possible Nambu-Goto cusp spectra with the asymptotic form $\mathop{\tilde{\!κ}}(ω) \propto ω^{-n/(2n-1)} ω^{-m/(2m-1)}$ where $n, m\geq 2$. We investigate the effect of realistic corrections to the Nambu-Goto description, such as those from backreaction and finite string width, which introduce a high frequency cutoff.
title New Massless Spectra from Cosmic String Cusps
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Theory
url https://arxiv.org/abs/2512.12258