Cosmic Strings in Hidden Sectors: 2. Cosmological and Astrophysical Signatures

TL;DR

This paper investigates the potential cosmological and astrophysical signatures of dark cosmic strings from hidden sectors, focusing on their detectability and constraints from current observations, especially for low-scale versus high-scale strings.

Contribution

It provides a comprehensive survey of observable effects of dark strings, including constraints and flux predictions, highlighting the current experimental limitations and theoretical bounds.

Findings

Low-scale (TeV) dark strings produce signatures below current detection thresholds.

Heavier strings (10^13-10^15 GeV) are inconsistent with nucleosynthesis constraints.

Current experiments do not constrain low-scale dark strings in hidden sectors.

Abstract

Cosmic strings can arise in hidden sector models with a spontaneously broken Abelian symmetry group. We have studied the couplings of the Standard Model fields to these so-called dark strings in the companion paper. Here we survey the cosmological and astrophysical observables that could be associated with the presence of dark strings in our universe with an emphasis on low-scale models, perhaps TeV. Specifically, we consider constraints from nucleosynthesis and CMB spectral distortions, and we calculate the predicted fluxes of diffuse gamma ray cascade photons and cosmic rays. For strings as light as TeV, we find that the predicted level of these signatures is well below the sensitivity of the current experiments, and therefore low scale cosmic strings in hidden sectors remain unconstrained. Heavier strings with a mass scale in the range 10^(13) GeV to 10^(15) GeV are at tension with nucleosynthesis constraints.