Type I Abelian Higgs strings: evolution and Cosmic Microwave Background constraints

Understand

We present results from the first simulations of networks of Type I Abelian Higgs cosmic strings to include both matter and radiation eras and Cosmic Microwave Background (CMB) constraints.

• In Type I strings, the string tension is a slowly decreasing function of the ratio of the scalar and gauge mass-squared, $\beta$.
• We find that the mean string separation shows no dependence on $\beta$, and that the energy-momentum tensor correlators decrease approximately in proportion to the square of the string tension, with additional O(1) correction factors which asymptote to constants below $\beta \lesssim 0.01$.
• Strings in models with low self-couplings can therefore satisfy current CMB bounds at higher symmetry-breaking scales.