Black hole with a scalar field as a particle accelerator
O. B. Zaslavskii
2017
International Journal of Modern Physics D
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 E_c.m. 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
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... eed 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_ϕϕ→ 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.
doi:10.1142/s0218271817501085
fatcat:455ohmwibjauvba6rhxeczciam