The derivation of transverse momenta from EAS observations

Abstract

Observations on EAS are examined from the point of view of deriving the transverse momenta of the secondaries produced in ultra-high-energy collisions.The lateral distributions of muons for various threshold energies provide useful experimental data, and a detailed analysis of this characteristic has been made. The most extensive results have been reported by Earnshaw et al. (1967), and a theoretical treatment of the lateral distributions expected, as a function of the transverse momentum of the parent pions, has been given by de Beer el al. (1966). A comparison appears to indicate mean transverse momenta much greater than the value of ~0.4 GeV/c found in the more direct observations on nucleon–nucleon collisions. However, an examination of the fluctuations in lateral distribution expected theoretically suggests that there is bias with practical EAS arrays leading to the selection of that fraction of the showers having unusually flat lateral distributions.The effect of applying a correction to allow for this bias is to reduce the derived mean transverse momenta considerably; the values being ~0.6 ± 0.2 GeV/c for pion interactions of mean energy ~200 GeV and 1.0 ± 0.3 GeV/c for interactions of mean energy ~4 000 GeV. These values are still significantly higher than the values measured more directly.