Long-lived staus from cosmic rays

The collision of a high energy cosmic ray with a nucleon in the upper atmosphere could produce long- lived heavy particles. Such particles would be very penetrating, since the energy loss in matter scales as the inverse mass, and could reach a neutrino telescope like IceCube from large zenith angles. Here we study this possibility and focus on the long- lived stau of supersymmetric models with a gravitino lightest supersymmetric particle. The signal would be a pair of muon- like parallel tracks separated by 50 m along the detector. We evaluate the background of muon pairs and show that any events from zenith angles above 80 degrees could be explained by the production of these heavy particles by cosmic rays. For light squark and gluino masses the number of these events in cubic kilometer neutrino telescopes is of the order of one per year.