Hunting long-lived gluinos at the Pierre Auger Observatory
Luis A. Anchordoqui, Antonio Delgado, Carlos A. Garc\ ' { \ i} a Canal, and Sergio J. Sciutto

Eventual signals of split sypersymmetry in cosmic ray physics are analyzed in detail. The study focusses particularly on quasi-stable colorless $R$-hadrons originating through confinement of long-lived gluinos (with quarks, anti-quarks, and gluons) produced in $pp$ collisions at astrophysical sources. Because of parton density requirements, the gluino has a momentum which is considerable smaller than the energy of the primary proton, and so production of heavy (mass $\sim 500~{\rm GeV}$) $R$-hadrons requires powerful cosmic ray engines able to accelerate particles up to extreme energies, somewhat above $10^{13.6}~{\rm GeV}.$ Using a realistic Monte Carlo simulation with the AIRES engine, we study the main characteristics of the air showers triggered when one of these exotic hadrons impinges on a stationary nucleon of the Earth atmosphere. We show that $R$-hadron air showers present clear differences with respect to those initiated by standard particles. We use this shower characteristics to construct observables which may be used to distinguish long-lived gluinos at the Pierre Auger Observatory.

© 2008 The American Physical Society.