TeV and Superheavy Particles from Supersymmetric Topological Defects, the Extragalacticγ-ray Background, and the Highest Energy Cosmic Rays

Cosmic topological defects in a wide class of supersymmetric theories can simultaneously be sources of Higgs bosons of $\mathrm{mass}\sim \mathrm{supersymmetry}$ breaking $\mathrm{scale}\sim \mathrm{TeV}$, as well as superheavy gauge bosons of $\mathrm{mass}\sim \eta \gg 1\mathrm{TeV}$, $\eta$ being the gauge symmetry breaking scale. Decay of these Higgs and gauge bosons may contribute significantly to the extragalactic diffuse $\gamma$-ray background (EDGRB) above $\sim 10\mathrm{GeV}$ and explain the highest energy cosmic ray (HECR) flux above $\sim {10}^{11}\mathrm{GeV}$, respectively. Cosmic strings with $\eta$ much above ${10}^{14}\mathrm{GeV}$ overproduce both HECR and EDGRB, and hence are ruled out, if massive particle radiation is their dominant energy loss mechanism.