Particle acceleration near a rotating charged black hole in 4D Einstein-Gauss-Bonnet gravity

Abstract

We investigate the horizon structure and ergosphere in a charged rotating black hole within 4D Einstein-Gauss-Bonnet gravity, which introduces additional parameters (Q) because of the charge and Gauss-Bonnet parameter (β), besides the mass (M) and rotation parameter (a). Interestingly, for each value of the parameter Q (β), there is a critical GB parameter $\beta ={\beta }_E$ ($Q=Q_E$) that corresponds to an extremal black hole with degenerate horizons. For $\beta <{\beta }_E$ ($Q<Q_E$), it describes a non-extremal black hole with two horizons, and for $\beta >{\beta }_E$ ($Q>Q_E$), no black hole exists. The extremal value ${\beta }_E$ ($Q_E$) is also affected by the GB parameter α and the ergosphere. We also study the collision of two equal-mass particles near the horizon of this black hole and explicitly show the effect of the parameter β (Q). The innermost stable circular orbits (ISCO) and the effective potential, which governs the motion of particles in spacetime, have been analyzed for different parameter values. The centre-of-mass energy ($E_{\mathrm{CM}}$) depends on the rotation parameter a and the parameters β and Q. We investigate the $E_{\mathrm{CM}}$ of two colliding particles near the horizon for both extremal and non-extremal cases. It is shown that in extremal cases, when one of the colliding particles has a critical angular momentum, the $E_{\mathrm{CM}}$ can be arbitrarily high, suggesting that the charged rotating in 4D Einstein-Gauss-Bonnet gravity can function as a particle accelerator. Despite the complexity of the BH solution, an exact expression for the thermodynamic quantities of black holes, such as the mass, Hawking temperature, and entropy, is derived in terms of the horizon radius. These quantities show significant deviations from the Kerr solution because of the influence of the Gauss-Bonnet parameter and electric charge.