An analysis of the nuclear interactions of high energy cosmic rays

Abstract

A study of kaon production in high energy nucleon-air nucleus collisions in the atmosphere; has been made based on the muon momentum spectrum at sea level. Starting from the measured vertical momentum spectrum the spectra at zenith angles between 75º and 90º have been predicted for various admixtures: of kaons and pions, taking into account all decay modes: of both charged and neutral kaons. The predicted values are compared with the intensities measured using the Durham horizontal muon spectrographs Although the method of computation allows the spectra to be predicted to an accuracy of 1% the present statistical errors on both the vertical and horizontal intensities are such that only an upper limit to R, the ratio of intensities at production of kaons to pions of all charge states, can be given; this has a value of about kOfo over a range of mesoa energies from about 70 G-eV to 1000 GeV. In order to extend the determination of the value of R to lower and higher energies respectively, reviews have been made of measurements of muon polarization at sea level and of the intensity of the electro magnetic cascades at various heights in the atmosphere. Combining the three methods an estimate is given of R over a range of meson energies from. 3 GeV tc 5000 GeV. If R is taken to be independent of energy a value of 20% would fit the data best over the whole energy range, but the error on this value approaches ± 20%.Comparing R with Ri, the observed ratio of numbers of non-pions to pions produced in individual interactions, it is concluded that, provided that the majority of non-pions are kaons, there is no evidence for the effective mean energies of pions and kaons from individual nuclear interactions being different in the range of primary energies from 10 GeV to 10(^5) GeV. Using the measured vertical spectrum of muons the energy spectra and angular distribution of neutrinos at sea level are calculated. The information is used in the interpretation of the preliminary results from, the Tata Institute-Osaka-Durham joint neutrino experiment in progress at the Kolar Gold Field Comparison of observed rates of events with rates predicted from extrapolation to higher energies of machine results on neutrino-nucleus collisions indicates that the cross-section for inelastic interactions continues to rise above 10 GeV Support for this conclusion is provided by the first results of the Case Institute-Witwatersrand University neutrino experiment. The possibility is discussed of detecting the hypothetical Intermediate Boson of weak interactions.