Cosmic rays and large extra dimensions
Sep, 2001Citations per year
Abstract:
We have proposed that the cosmic ray spectrum "knee", the steepening of the cosmic ray spectrum at energy E \gsim 10^{15.5} eV, is due to "new physics", namely new interactions at TeV cm energies which produce particles undetected by the experimental apparatus. In this letter we examine specifically the possibility that this interaction is low scale gravity. We consider that the graviton propagates, besides the usual four dimensions, into an additional , compactified, large dimensions and we estimate the graviton production in collisions in the high energy approximation where graviton emission is factorized. We find that the cross section for graviton production rises as fast as , where is the fundamental scale of gravity in dimensions, and that the distribution of radiating a fraction of the initial particle's energy into gravitational energy (which goes undetected) behaves as . The missing energy leads to an underestimate of the true energy and generates a break in the {\sl inferred} cosmic ray spectrum (the "kne"). By fitting the cosmic ray spectrum data we deduce that the favorite values for the parameters of the theory are TeV and .Note:
- 8 pages, 1 figure
- cosmic radiation: energy spectrum
- new interaction
- gravitation
- space-time: higher-dimensional
- p p: interaction
- graviton: hadroproduction
- cross section: energy dependence
- energy loss
- numerical calculations: interpretation of experiments
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