Black hole with a scalar field as a particle accelerator

Abstract

We consider stationary axially symmetric black holes with the background scalar field and test particles that can interact with this field directly. Then, particle collision near a black hole can lead to the unbounded energy in the centre of mass frame (contrary to some recent claims in literature). This happens always if one of particles is neutral whereas another one has nonzero scalar charge. Kinematically, two cases occur here. (i) A neutral particle approaches the horizon with the speed of light while the velocity of the charged one remains separated from it (this is direct analogue of the situation with collision of geodesic particles.). (ii) Both particles approach the horizon with the speed almost equal to that of light but with different rates. As a result, in both cases the relative velocity also approaches the speed of light, so that $E_{c.m.}$  becomes unbounded. We consider also a case when the metric coefficient $g_{\varphi \varphi }\to 0$ near a black hole. Then, overlap between the geometric factor and the presence of the scalar field opens additional scenarios in which unbounded energy $E_{c.m.}$ is possible as well. We give a full list of possible scenarios of high-energy collisions for the situations considered.

26 pages. Substantially expanded. We present full list of possible scenarios with unbounded E_c.m. for a given system

References in corpus (4)

• Acceleration of particles by nonrotating charged black holes
• Particle Collisions on Stringy Black Hole Background
• Naked singularities as particle accelerators
• High energy particle collisions and geometry of horizon

Cited by in corpus (6)

• Motion and collision of particles in rotating linear dilaton black hole
• Schwarzschild black hole surrounded by quintessential matter field as an accelerator for spinning particles
• Particle collisions near a three-dimensional warped AdS black hole
• Collision of particles near a three-dimensional rotating Hořava AdS black hole
• Kinematic censorship as a constraint on allowed scenarios of high energy particle collisions
• Motion and collision of particles near DST Black holes