Mass and angular momentum of black holes in low-energy heterotic string theory

TL;DR

This paper develops a formalism to compute conserved charges like mass and angular momentum for black holes in heterotic string theory, using an off-shell ADT approach that is conformally invariant and applicable directly in the string frame.

Contribution

It generalizes the ADT formalism to off-shell level and applies it to compute black hole charges in heterotic string theory without frame transformation.

Findings

Successfully computes mass and angular momentum of Kerr-Sen black hole.

Calculates charges of five-dimensional rotating charged black string.

Formalism is conformally invariant and applicable in the string frame.

Abstract

We investigate conserved charges in the low-energy effective field theory describing heterotic string theory. Starting with a general Lagrangian that consists of a metric, a scalar field, a vector gauge field, together with a two-form potential, we derive off-shell Noether potentials of the Lagrangian and generalize the Abbott-Deser-Tekin (ADT) formalism to the off-shell level by establishing one-to-one correspondence between the ADT potential and the off-shell Noether potential. It is proved that the off-shell generalized ADT formalism is conformally invariant. Then we apply the formulation to compute mass and angular momentum of the four-dimensional Kerr-Sen black hole and the five-dimensional rotating charged black string in the string frame without a necessity to transform the metrics into the Einstein frame.