Rotating Hayward's regular black hole as particle accelerator

TL;DR

This paper investigates how rotating Hayward's regular black holes can serve as particle accelerators, demonstrating that extremal cases can achieve arbitrarily high collision energies near the horizon, similar to Kerr black holes.

Contribution

It extends the BSW process analysis to Hayward's regular black holes, showing the effect of the deviation parameter g on extremality and collision energy divergence.

Findings

Extremal Hayward black holes can produce infinite collision energies.

Non-extremal cases have finite maximum collision energies that increase with g.

Critical parameters for extremality depend on the deviation parameter g.

Abstract

Recently, Ban\~{a}dos, Silk and West (BSW) demonstrated that the extremal Kerr black hole can act as a particle accelerator with arbitrarily high center-of-mass energy ($E_{CM}$) when the collision takes place near the horizon. The rotating Hayward's regular black hole, apart from Mass ($M$) and angular momentum ($a$), has a new parameter $g$ ($g>0$ is a constant) that provides a deviation from the Kerr black hole. We demonstrate that for each $g$, with $M=1$, there exist critical $a_{E}$ and $r_{H}^{E}$, which corresponds to a regular extremal black hole with degenerate horizon, and $a_{E}$ decreases and $r_{H}^{E}$ increases with increase in $g$. While $a<a_{E}$ describe a regular non-extremal black hole with outer and inner horizons. We apply BSW process to the rotating Hayward's regular black hole, for different $g$, and demonstrate numerically that $E_{CM}$ diverges in the vicinity of the horizon for the extremal cases, thereby suggesting that a rotating regular black hole can also act as a particle accelerator and thus in turn may provide a suitable framework for Plank-scale physics. For a non-extremal case, there always exist a finite upper bound of $E_{CM}$, which increases with deviation parameter $g$.