Small Horizons

TL;DR

This paper classifies all near-horizon geometries of supersymmetric black holes in a five-dimensional supergravity theory with higher derivatives, revealing conditions for regular horizons and scalar hair based on conformal factors.

Contribution

It provides a complete classification of near-horizon geometries in this theory, including new solutions with scalar hair and non-trivial conformal factors.

Findings

Horizon geometries are conformal to S^3, S^1*S^2, or T^3.

Constant conformal factor implies maximally supersymmetric solutions.

Non-constant conformal factor satisfies a vortex equation, allowing scalar hair.

Abstract

All near horizon geometries of supersymmetric black holes in a N=2, D=5 higher-derivative supergravity theory are classified. Depending on the choice of near-horizon data we find that either there are no regular horizons, or horizons exist and the spatial cross-sections of the event horizons are conformal to a squashed or round S^3, S^1 * S^2, or T^3. If the conformal factor is constant then the solutions are maximally supersymmetric. If the conformal factor is not constant, we find that it satisfies a non-linear vortex equation, and the horizon may admit scalar hair.