Long-Lived Superheavy Particles in Dynamical Supersymmetry-Breaking Models in Supergravity

Abstract

Superheavy particles of masses $\simeq 10^{13}-10^{14} GeV$ with lifetimes $\simeq 10^{10}-10^{22} years$ are very interesting, since their decays may account for the ultra-high energy (UHE) cosmic rays discovered beyond the Greisen-Zatsepin-Kuzmin cut-off energy $E \sim 5 \times 10^{10} GeV$. We show that the presence of such long-lived superheavy particles is a generic prediction of QCD-like SU(N_c) gauge theories with N_f flavors of quarks and antiquarks and the large number of colors N_c. We construct explicit models based on supersymmetric SU(N_c) gauge theories and show that if the dynamical scale $Λ\simeq 10^{13}-10^{14} GeV$ and N_c = 6-10 the lightest composite baryons have the desired masses and lifetimes to explain the UHE cosmic rays. Interesting is that in these models the gaugino condensation necessarily occurs and hence these models may play a role of so-called hidden sector for supersymmetry breaking in supergravity.