Do Global String Loops Collapse to Form Black Holes?

TL;DR

This paper investigates whether global cosmic string loops can avoid black hole formation through Goldstone boson emission, finding a critical size below which loops do not collapse, especially relevant for GUT scale strings.

Contribution

It extends previous work on gauged strings by analyzing global strings, identifying a critical loop size that prevents black hole formation due to Goldstone boson emission.

Findings

Loops smaller than the critical size do not form black holes.

Critical size is much larger than the current horizon for GUT scale strings.

Goldstone boson emission influences the collapse dynamics of global string loops.

Abstract

Hawking has shown that the emission of gravitational radiation cannot prevent circular loops of gauged cosmic strings from collapsing into black holes. Here we consider the corresponding question for global strings: can Goldstone boson emission prevent circular loops of global cosmic strings from forming black holes? Our results show that for every value of the string tension there is a certain critical size below which the circular loop does not collapse to form a black hole. For GUT scale strings, this critical size is much larger than the current horizon.