Cosmogenic Neutrinos and New Physics Signal at Neutrino Telescopes

Cosmogenic neutrinos reach the Earth with energies around 109 GeV, and their interactions with matter will be measured in upcoming experiments (Auger, IceCube). Models with extra dimensions and the fundamental scale at the TeV could imply signals in these experiments. In particular, besides the production of microscopic black holes by cosmogenic neutrinos, gravity-mediated interactions at larger distances (that can be calculated in the eikonal approximation) can take place. In these processes a neutrino of energy Ev interacts elastically with a parton inside a nucleon, loses a small fraction y of its energy, and starts a hadronic shower of energy yEv << Ev. We show that for the expected fluxes of cosmogenic neutrinos these elastic processes give a stronger signal than black hole production in neutrino telescopes and that the energy distribution of contained hadronic showers can help to distinguish between eikonal and black hole or Standard Model events. On the other hand, the absence of any signal at IceCube would imply a bound of MD > or approx. 5 TeV