Particle identification from track density for 4 GeV/c π −p reactions in the 80 cm hydrogen bubble chamber

Abstract

In analysis of e (as Fe/sup 59 /sup -/ p collisions at 4 Bev/c in photographs taken at the CERN proton synchrotron, three types of information are available; (1) the kinematics of the event, (2) the density of the positive tracks, and (3) information from the scanning table. Results of a study of these three sources of information with regard to agreement between them, their efficiency, and their complementarity are summarized. For almost all the 74 2- prong events and 23 4prong events studied, a definite decision could be made as to which reaction took place. Up to a momentum of st run. Concent 2 Bev/ c, track density measurement is an efficient tool for particle and event identification, agreeing with and supplementing the kinematic fit. Track density also permits events with several neutrals to be subdivided into two groups. If the kinematic fit accepts two or more hypotheses with reasonable X/sup 2/, it is very dangerous to have a prejudice in favor of the hypothesis with the smallest X/ sup 2/. (A.G.W.)