Hunting long-lived gluinos at the Pierre Auger Observatory

Abstract

Eventual signals of split supersymmetry in cosmic ray physics are analyzed in detail. The study focuses particularly on quasistable colorless R -hadrons originating from confinement of long-lived gluinos (with quarks, antiquarks, and gluons) produced in p p collisions at astrophysical sources. Because of parton density requirements, the gluino has a momentum which is considerably smaller than the energy of the primary proton, and so production of heavy (mass ∼ 500 GeV ) R -hadrons requires powerful cosmic ray engines able to accelerate particles up to extreme energies, somewhat above 10 13.6 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’s atmosphere. We show that R -hadron air showers present clear differences with respect to those initiated by standard particles. We use these shower characteristics to construct observables which may be used to distinguish long-lived gluinos at the Pierre Auger Observatory.