Muons from high-energy cosmic photino

Abstract

The muon production at photino-nucleon\((\bar \gamma \mathcal{N})\) interaction for high-energy photino (E⊂)104GeV) is studied. The production of muons is the result of the creation and the subsequent decay of charmed hadrons. The quark subprocess considered is\(\bar \gamma + g \to c(\bar c) + \mathop c\limits^ \simeq (\tilde c)\). In the calculation the chains of reactions\(\tilde c \to c \to D \to \mu \) and c→D→μ are taken into account. The main contribution to a muon flux is given by the production of\(\bar c\)-quark. Muon fluxes from high-energy cosmic photino absorbed in water (ground) and atmosphere are calculated. For muon energy above −2.103GeV the ration of equilibrium underground muon flux to photino flux\(r_\mu ^{\bar \gamma } (E) = j_\mu (E)/j_{\bar \gamma } (E)\) decreases with a rise of energyE because of nuclear interactions of D-mesons at decay length, and at energy −2·105GeV the vertical muon flux created in the atmosphere becomes comparable with underground equilibrium flux. The production of muons by photino is less effective than by neutrino: the ratio\(r_\mu ^{(\nu )} = j_\mu (E)/j_{\nu _\mu + \bar \nu _\mu } (E)\) is higher than\(r_\mu ^{(\tilde \gamma )} \) for all energies. On the other hand, the cross-section at superhigh energies is by a factor of −102 larger than the\(\nu \mathcal{N}\) cross-section. This fact gives some signature of photino flux from source in case of combined observations by sea-level EAS arrays and underground detectors: large EAS flux and relatively small flux of underground high-energy muons.