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Pion-to-proton ratio for unaccompanied high-energy cosmic-ray hadrons at mountain altitude using transition-radiation detector

Journal Article · · Phys. Rev. D; (United States)
A transition-radiation (TR) detector, consisting of 24 modules of styrofoam radiators and multiwire proportional chambers, and an ionization calorimeter have been used to measure the pion-to-proton ratio among the unaccompanied cosmic-ray hadrons at a mountain altitude of 730 g cm/sup -2/. Using the characteristics of the TR detector obtained from calibrations with particle beams at accelerators, the ..pi../p ratio has been determined for cosmic-ray hadrons as ..pi../p = 0.96 +- 0.15 for hadron energy = 400--800 GeV, and ..pi../p = 0.45 +- 0.25 for energy >800 GeV. Monte Carlo simulations of hadron cascades in the atmosphere using the approximate criterion of unaccompaniment suggest that the observed ..pi../p ratio as well as the previously reported neutral-to-charge ratio can be understood by assuming a value of about (1/3) for the charge exchange in nucleon--air-nucleus inelastic interactions at energies above 400 GeV.
Research Organization:
Department of Physics and Astronomy, University of Maryland, College Park, Maryland 20742
OSTI ID:
5925770
Journal Information:
Phys. Rev. D; (United States), Journal Name: Phys. Rev. D; (United States) Vol. 27:9; ISSN PRVDA
Country of Publication:
United States
Language:
English