De-singularizing the extremal GMGHS black hole via higher derivatives corrections

Understand

The Gibbons-Maeda-Garfinkle-Horowitz-Strominger (GMGHS) black hole is an influential solution of the low energy heterotic string theory.

• As it is well known, it presents a singular extremal limit.
• We construct a regular extension of the GMGHS extremal black hole in a model with $\mathcal{O}(\alpha')$ corrections in the action, by solving the fully non-linear equations of motion.
• The de-singularization is supported by the $\mathcal{O}(\alpha')$-terms.