The Komar charge in presence of the Holst term and the gravitational Witten effect

Abstract: In the first-order formalism, the Einstein--Hilbert action can be modified by the addition of a Holst term multiplied by the Barbero parameter $\alpha$. This modification breaks parity although it does not affect the equations of motion. We show that the standard Komar charge is also modified by the addition of a topological term multiplied by the Barbero parameter $\alpha$. For the Killing vector that generates time translations, the value of the Komar integral at infinity is modified by the addition of a term proportional to the NUT charge $N$ and the parity-breaking Barbero parameter. Thus, as in the standard Witten effect, a non-vanishing NUT charge $N$ induces a non-vanishing mass $\alpha N$.