Fermion Emission from Five-Dimensional Black Holes

TL;DR

This work presents a semiclassical calculation of spin-1/2 fermion emission from nonrotating charged black holes in five-dimensional N=8 supergravity. By solving the Dirac equation in the black-hole background and employing a horizon–asymptotic region matching, the authors derive greybody factors and show their structure mirrors that of scalar emissions, consistent with an effective string theory description. A key result is the explicit dependence of the emission rate on the black-hole charges, with certain fermion modes enhanced or suppressed, and a near-extremal limit where the greybody factor approaches a horizon-area factor. The findings reinforce the universality of the effective string picture for black-hole microphysics and highlight the role of horizon symmetries in organizing fermionic emissions, while setting the stage for incorporating full fermionic worldsheet dynamics in future work.

Abstract

We calculate semiclassically the emission rate of spin 1/2 particles from charged, nonrotating black holes in D=5,N=8 supergravity. The relevant Dirac equation is solved by the same approximation as in the bosonic case. The resulting expression for the emission rate has a form which is predicted from D-brane effective field theory.