Brane-Production and the Neutrino-Nucleon cross section at Ultra High   Energies in Low Scale Gravity Models
  The origin of the ultra high energy cosmic ray (UHECR) showers has remained as a mystery among particle physicists and astrophysicists. In low scale gravity models, where the neutrino-nucleon cross section rises to typical hadronic values at energies above $10^{20}$ eV, the neutrino becomes a candidate for the primary that initiates these showers. We calculate the neutrino-nucleon cross section at ultra high energies by assuming that it is dominated by the production of p-branes. We show, using a generalized Randall-Sundrum model, that the neutrino-nucleon cross-section at neutrino energies of $10^{11}$ GeV is of the order of 100 mb, which is required for explaining UHECR events. Similar result also follows in other models such as the Lykken-Randall model. 
Pankaj Jain, Supriya Kar and Sukanta Panda