Revisiting Scattering Enhancement from the Aharonov-Bohm Effect

TL;DR

This paper reevaluates the scattering of charged particles by Aharonov-Bohm cosmic strings, demonstrating that previous infinite cross section results are suppressed when considering the string core size, challenging earlier claims of enhancement.

Contribution

The study applies modern generalized global symmetries and discrete gauge theory to clarify the scattering behavior, showing no enhancement as previously suggested.

Findings

Scattering cross section is finite and suppressed by the string core size.

No Callan-Rubakov-like enhancement occurs in the revised analysis.

Topological Aharonov-Bohm effects do not lead to dramatic dynamical consequences for single particles.

Abstract

We revisit the problem of a charged particle scattering off of an Aharonov-Bohm cosmic string. A classic computation gave an infinite total scattering cross section, leading to a Callan-Rubakov-like enhancement which can have important implications on baryon number asymmetry in the early universe. However, unlike the Callan-Rubakov effect, the Aharonov-Bohm interaction is topological and thus it is surprising that it leads to such a dramatic dynamical effect for single particle scattering. We reexamine this old problem through the modern lens of generalized global symmetries by embedding Aharanov-Bohm strings in a discrete gauge theory. We show that the scattering cross section is suppressed by the core size and there is thus no Callan-Rubakov-like enhancement.