Neutrinos as the source of ultrahigh energy cosmic rays in extra dimensions

Abstract

If neutrinos are to be identified with the primary source of ultrahigh energy cosmic rays ͑UHECR͒, their interaction on relic neutrinos is of great importance in understanding their long intergalactic journey. In theories with large compact dimensions, the exchange of a tower of massive spin-2 gravitons ͑Kaluza-Klein excitations͒ gives an extra contribution to → f f and ␥␥ processes along with the opening of a new channel for the neutrinos to annihilate with the relic cosmic neutrino background →G kk to produce bulk gravitons in the extra dimensions. This will affect their attenuation. We compute the contribution of these Kaluza-Klein excitations to the above processes and find that for parameters of the theory constrained by supernova cooling, the contribution does indeed become the dominant contribution above ͱsӍ300 GeV.

Brane decay of a (4+n)-dimensional rotating black hole. III: spin-1/2 particles

“…This type of trans-planckian particle collision could be achieved in various environments, such as at ground-based colliders [5] or in high energy cosmic-ray interactions in the atmosphere of the earth [6] (for an extensive discussion of the phenomenological implications and additional references, see the reviews [7,8,9]). The black holes produced with horizon radius r h ≪ L are submerged into the higher-dimensional spacetime, which modifies their properties (horizon radius, temperature, entropy, life-time etc.)…”

Black Holes in Theories With Large Extra Dimensions: A Review

“…In the context of theories with large extra dimensions, the trans-Planckian energy regime may lie slightly above the TeV scale. This raises the exciting possibility that particle collisions with trans-Planckian energies may take place, in the near future, at ground-based accelerators 70,71,72,73,74 , or they may even already take place in the atmosphere of the earth 75,76,77,78 . In the first case, accelerated particles (protons or nuclei) collide at center-of-mass energies √ s > M * at ground-based accelerators; if the impact parameter is smaller than a critical value b c , a higher-dimensional black hole will be formed.…”

Bulk and brane decay of a (4+n)-dimensional Schwarzschild–de Sitter black hole: Scalar radiation

“…If only gravity is allowed to propagate in the (4 + n)-dimensional bulk while all other fields are confined to a (3+1)-dimensional brane, the size of the extra dimensions can be as large as 1 mm and the related fundamental Planck scale, M * , can be as low as 1 TeV [1]. A distinctive feature of the scenario with Large Extra Dimensions [1] is that, above the scale of decompactification, gravitational interactions become strong, with the highly suppressed 4-dimensional Newton's constant, κ A particularly exciting proposal is that of the creation of mini black holes [4], either at colliders [5] or in high energy cosmic-ray interactions [6] (for an extensive discussion of the phenomenological implications as well as for a more complete list of references, see the recent reviews [7,8]). If such black holes do indeed form during high-energy particle collisions, with center-of-mass energies greater than the fundamental Planck scale M * , we expect them to evaporate through the emission of Hawking radiation, similarly to their 4-dimensional counterparts -for a detailed discussion of the properties of these microscopic black holes formed in a flat, higher-dimensional spacetime, see Refs.…”