Scattering of scalar, electromagnetic, and Dirac fields in an asymptotically flat regular black hole supported by primordial dark matter

TL;DR

This paper analyzes how scalar, electromagnetic, and Dirac fields scatter off a regular black hole supported by dark matter, revealing effects of regularity on absorption and confirming the QNM/GBF correspondence.

Contribution

It provides a detailed WKB analysis of grey-body factors in a novel regular black hole model and tests the QNM/GBF correspondence with high accuracy.

Findings

Increasing regularity lowers potential barriers and shifts transmission to lower frequencies.

Absorption cross sections are enhanced with higher regularity.

Good agreement (around 1%) between WKB grey-body factors and those reconstructed from quasinormal modes.

Abstract

We study grey-body factors and absorption cross sections for massless scalar, electromagnetic, and Dirac fields in the exact asymptotically flat regular black-hole geometry supported by a phantom Dirac--Born--Infeld scalar. In the black-hole branch all three sectors are governed by single-barrier effective potentials, which allows a direct 6th-order WKB treatment of the scattering problem and a comparison with the recent quasinormal-mode/grey-body-factor correspondence. We show that increasing the regularity parameter lowers the barriers, shifts transmission to lower frequencies, and enhances the absorption cross sections in all three sectors. By comparing the direct WKB grey-body factors with those reconstructed from the lowest quasinormal modes, we explicitly test the QNM/GBF correspondence and find good agreement, typically at the level of $10^{-2}$ or better.