The role of hyperons in extensive air showers and in other high-energy phenomena

Abstract

Experimental results obtained at the Geneva proton synchrotron support the hypothesis that in high energy nuclear collisions the particle which carries away most of the energy is often a hyperon. In proton collisions at 25 GeV this occurs in about 20% of the cases. The fraction of hyperons appears to increase further with increasing proton energy and probably reaches a value close to 50% for energies above ∼ 1000 GeV. It is shown that in the atmosphere most pions, μ-mesons, and γ-rays in the energy interval from a few times 1011 eV to about 1014 eV are due to hyperon decay rather than to direct pion production and that a large fraction of the primary energy appearing in the electron-photon component is transmitted through this process. The presence of hyperons in the nuclear cascade in the core of air showers gives rise to a large number of characteristic phenomena, both in the atmosphere and underground, some of which may be related to phenomena recently reported in the literature. Since hyperon decays result in a large excess of negative over positive mesons, charged eterminations on μ-mesons underground may give information on the relative yield of nucleons, nuclear isobars, and of strangeness one and strangeness two hyperons at high energies. It is further shown that the simultaneous arrival of two or more μ-mesons at great depth below ground signals the arrival and interaction of a complex primary nucleus at the top of the atmosphere.