Higher-dimensional gravity term cures a curvature singularity in rotating black holes

Working in five-dimensional Einstein-Gauss-Bonnet gravity, the authors construct the first known exact analytic near-horizon solution for a singly rotating black hole that has finite curvature invariants across a meaningful range of parameters. The higher-derivative Gauss-Bonnet term acts as a geometric regulator, but rotation must stay below a bound set by the coupling strength or the singularity returns. Mapping the full parameter space reveals distinct regular, marginal, and singular regimes. A notable complication emerges: the same corrections that smooth the curvature disrupt the standard thermodynamic framework for Killing horizons.