Greybody Factors for Scalar Fields emitted by a Higher-Dimensional Schwarzschild-de-Sitter Black-Hole

TL;DR

This paper derives analytical expressions for greybody factors of scalar fields emitted by higher-dimensional Schwarzschild-de-Sitter black holes, analyzing their dependence on spacetime and scalar properties, including the cosmological constant's dual role.

Contribution

It provides the first analytical derivation of greybody factors considering arbitrary modes, non-minimal coupling, and the cosmological constant's effects in higher-dimensional black-hole spacetimes.

Findings

Greybody factors depend on scalar and spacetime parameters.

The cosmological constant can enhance or suppress emission.

Low-energy behaviour of scalar emission is characterized.

Abstract

In this work, we consider the propagation of scalar particles in a higher-dimensional Schwarzschild-de-Sitter black-hole spacetime, both on the brane and in the bulk. Our analysis applies for arbitrary partial modes and for both minimal and non-minimal coupling of the scalar field. A general expression for the greybody factor is analytically derived in each case, and its low-energy behaviour is studied in detail. Its profile in terms of scalar properties (angular-momentum number and non-minimal coupling parameter) and spacetime properties (number of extra dimensions and cosmological constant) is thoroughly investigated. In contrast to previous studies, the effect of the cosmological constant is taken into account both close to and far away from the black-hole horizon. The dual role of the cosmological constant, that may act either as a helping agent to the emission of scalar particles or as a deterring effect depending on the value of the non-minimal coupling parameter, is also demonstrated.