EYM equations in the presence of q-stars is scalar-tensor gravitational theories

TL;DR

This paper investigates Einstein-Yang-Mills equations with non-topological solitons in scalar-tensor theories, analyzing how different parameters influence soliton star solutions within Brans-Dicke and related models.

Contribution

It extends the study of soliton solutions to scalar-tensor gravitational theories, including Brans-Dicke, and explores parameter effects on these solutions.

Findings

Reproduces GR results in the limit of large coupling constants.

Numerical solutions describe soliton stars with non-abelian gauge fields.

Parameter variations significantly affect soliton properties.

Abstract

We study Einstein-Yang-Mills equations in the presence of a gravitating non-topological soliton field configuration consisted of a Higgs doublet, in Brans-Dicke and general scalar-tensor gravitational theories. The results of General Relativity are reproduced in the $\omega_{\textrm{BD}},\omega_0\to\infty$ limit. The numerical solutions correspond to a soliton star with a non-abelian gauge field. We study the effects of the coupling constant, the frequency of the Higgs field and the Brans-Dicke field on the soliton parameters