Particle collisions near a Kerr-like black hole in Brans–Dicke theory

Abstract

A recent discovery in 2009 by Bañados, Silk and West (BSW), which generated a lot of interest, involves the arbitrary high center-of-mass (c.m.) energies for free particle collisions at the horizon of an extreme kerr black hole when one of the free particles has a critical value of the angular momentum. In light of this we consider the rotating Kerr-like black hole solution in Brans-Dicke theory and study the motion of scalar test charges in the vicinity of the black hole horizon. We show that the interaction of the test scalar charges with the background scalar field in this spacetime suppresses the c.m. energy for collisions occurring near the event horizon, and the value of the c.m. energy there, is finite irrespective of whether the black hole is extreme or not and its value is also independent of the angular momenta of the colliding test charges.