An analysis of 5 Gev/c π(^+)P collisions involving many neutral secondary particles

Abstract

This thesis contains an account of some of the work carried out by the author whilst at Durham University. The work has been carried out by the High Energy Nuclear Physics Group of the University of Durham in collaboration with similar groups from the Universities of Bonn, Nijmegen, Paris, Turin and Strasbourg. Bubble Chamber analysis is concentrated on those events in which at most there is only one neutral particle involved. The remainder, the NOFIT events, can often amount to a considerable proportion of the total events unless these are analysed they represent a loss in the total knowledge of the physics of the interaction. The events, in a sense, are of lower quality than the normal sets of events that are analysed, since the latter have undergone the fitting process which reduces the effects of errors of measurements and also reduces ambiguities of interpretation. In this thesis events produced by 5 Gev/c positive pions on protons, in which there are two charged secondary particles and two or more neutral particles have been selected for analysis. The problem of ambiguity of identity of the charged secondaries is discussed at length and a successful method has been devised to divide clearly these two pronged events into those with Pπ(^+) and those with π(^+) π(^+) as the two charged secondaries. For each of these groups the effects of measuring errors on the estimated invariant masses is considered in detail and the expected mass resolution in each invariant mass combinations is determined. With the resolution of ambiguity and the calculated precision of mass determination, resonant particle production is sought. Clear signals corresponding to the production of ∆((^++) ɱ , f , A(_1)(^+) and A(_2)(^+) are seen. There is some evidence for the N(^x+) (1700) resonance. The consideration of mass resolution is preceded by a general consideration of the accuracy of the determination of momentum in the chamber.