Greybody factors for a black hole in massive gravity

TL;DR

This paper investigates the greybody factors affecting Hawking radiation from Schwarzschild-dS black holes in massive gravity, analyzing scalar fields with minimal and non-minimal couplings through numerical and analytical methods.

Contribution

It provides the first detailed analysis of greybody factors in massive gravity black holes, including effects of St"uckelberg field coupling and different black hole regimes.

Findings

Greybody factors are modified by the background geometry.

Coupling with St"uckelberg fields reduces particle emission.

Resonances appear in greybody factors due to non-trivial couplings.

Abstract

An exact solution was recently found in the massive gravity theory having the form of Schwarzschild-dS black holes with some additional background fields. Hawking radiation will occur at the event and cosmological horizons having the blackbody spectrum, which will be modified by the geometry outside the black hole. In this paper, we study the greybody factors of a test scalar, considering its minimal coupling with the background geometry. The case of small black holes with the horizon radius much smaller than the cosmological dS radius is studied numerically. The case of near-extremal black holes with the horizon radius comparable to the cosmological dS radius is studied analytically. In addition, we considered the coupling of the test field with the background {St\"uckelberg} fields, which in turn leads to reductions in particle emission and some non-trivial features (resonances) in the greybody factors.