Particle emission and gravitational radiation from cosmic strings: observational constraints

TL;DR

This paper investigates how particle emission and gravitational waves from cosmic string loops influence their distribution and observable signals, finding that current gamma-ray observations do not constrain the string tension.

Contribution

It models the effects of particle emission on cosmic string loops and assesses their impact on gravitational wave and gamma-ray backgrounds, providing new observational constraints.

Findings

High frequency cutoff in gravitational wave background is outside current detector range.

Diffuse gamma-ray background is not constraining for string tension Gμ.

Particle emission alters loop distribution and observational signatures.

Abstract

We account for particle emission and gravitational radiation from cosmic string loops to determine their effect on the loop distribution and observational signatures of strings. The effect of particle emission is that the number density of loops no longer scales. This results in a high frequency cutoff on the stochastic gravitational wave background, but we show that the expected cutoff is outside the range of current and planned detectors. Particle emission from string loops also produces a diffuse gamma ray background that is sensitive to the presence of kinks and cusps on the loops. However, both for kinks and cusps, and with mild assumptions about particle physics interactions, current diffuse gamma-ray background observations do not constrain $G\mu$.