Can we use gravity to produce ultra-high energy cosmic rays and neutrinos ?

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Written by Mandar Patil

Origin of ultra-high energy cosmic rays and neutrinos remains an enigma. All proposed mechanisms use electromagnetic interaction to accelerate changed particles. We propose for the first time, a mechanism that exclusively makes use of Gravity, rather than the electromagnetic forces. We show that it is possible to generate ultra-high energy particles in the overspinning Kerr geometry transcending Kerr bound by a small amount. We compute spectrum of the ultra-high energy particles and argue that its shape could serve as a powerful probe of particle physics. By solving the constraint equations in numerical relativity we show that the overspinning Kerr geometry could occur in the gravitational collapse scenario. It was also argued by Horava that overspinning spacetimes could be realized in the context of string theory. We also speculate on the other spacetime geometries where a similar acceleration mechanism could be at work.

Based on  Phys. Rev. D 93, 104015 (2016),  Phys. Rev. D 90, 124079 (2014).