Scalar and spinor fields in gravitating cosmic string spacetimes

TL;DR

This paper investigates how scalar and spinor fields scatter in a gravitating cosmic string spacetime, comparing non-abelian and abelian models, revealing oscillatory cross-sections and diffraction patterns.

Contribution

It introduces a detailed numerical analysis of scalar and spinor scattering in gravitating cosmic string backgrounds, including non-abelian and abelian cases, using a modified partial wave approach.

Findings

Total cross-section oscillates with incident momentum.

Angular scattering profiles resemble Fraunhofer diffraction patterns.

Differences between non-abelian and abelian models are characterized.

Abstract

We study the scattering behavior of scalar and spinor fields in the background of a gravitating cosmic string spacetime. The model explored here for the background vortex is non-abelian, becoming abelian in an appropriate limiting case. We adopted the formalism we developed in \cite{silva2021scattering}, modifying the standard partial wave approach. We apply the method for a scalar and also a fermion field interacting with the background spacetime with a nontrivial asymptotic structure. The spacetime metric, obtained numerically in \cite{de2015gravitating}, forms the basis of our state-of-the-art numerical study. We make an exhaustive analysis and compare all the results in the non-abelian model with the corresponding abelian one for both massless and massive fields. We analyze the field configuration's total cross-section and angular profile at small and large distances from the core. We show that the total cross-section oscillates with the incident momentum of the wave, as anticipated in \cite{silva2021scattering}, and also, the angular profile can be explained reasonably well with a Fraunhofer diffraction pattern, especially for the scalar field scattering.