A Study of High Energy Nuclear Interactions with Large Emulsion Cloud Chamber

Abstract

A large emulsion cloud chamber (E. C. C.) carried by a balloon was exposed at high altitude (October, 1963, Kobe). The characteristics of the interactions of high energy cosmic ray particles (\({\gtrsim}10^{13}\) eV) with other nuclei were examined. Forty-two events with energies higher than 10 12 eV were observed, from which the events of nuclear interactions in the carbon producer were selected. The transverse momenta of γ-rays which were the decay products of π°-mesons emitted from jets were estimated at 230 MeV/c (assuming that the P t distribution of γ-ray resembles that of π°'s, and the average P t value of π° is about twice that of γ). The curve of P t distribution does not fit the Gaussian form. In the energy region of about 10 12 eV, the energy spectrum can be fit by single power laws of 1.50±0.42 for Σ E γ , and 1.60±0.25 for E γ . There is no correlation between P t and E γ .