Identifying String Relics at AUGER?

The identification of string relics, or of other very massive states, at forthcoming ultra high energy cosmic rays experiments, requires a good reconstruction of the main properties of the extensive air showers produced by the collision of the primary protons with the atmosphere. In particular, the current hadronization models used in the simulations need to incorporate possible new interactions. We briefly discuss these aspects and then proceed by describing some of the observables which characterize the atmospheric shower. The linear growth of the multiplicities - as a function of the energy - for all the main particles in the shower can play an interesting role in an attempt to identify channels of missing energy due to a plausible dark matter component.