Cosmic ray induced micro black hole showers

Extended air showers originate from interactions between ultra-high-energy cosmic rays and nuclei in the Earth's atmosphere. At present there are some discrepancies between experimental observed properties of these air showers and theoretical predictions obtained by using standard hadronic interaction models for cosmic ray primaries with laboratory energies above 10^5 - 10^6 TeV. In this contribution, we will present a preliminary discussion of the possibility (in the framework of TeV gravity models) that shower development may begin with the production of a microscopic black hole (MBH) at the moment of the primary collision, which then evaporates and decays, by emitting gravitons and Standard Model quanta. From our preliminary investigations it appears that lepton distributions are more likely to reveal the presence of a MBH than photon distributions.