On the azimuthal effects of two prong πN and three prong DD events produced by 17.2 GeV/c π− mesons

Abstract

A deviation from isotropy in the azimuthal angular distribution of secondary particles of two and three prong pion-nucleon interactions is observed in emulsion at 17.2 GeV/c. Attempts are made using Monte Carlo calculations to interpret these azimuthal effects on the basis of (i) the kinematics of reactions π− p→pπ− (k π0) and π− p→nπ+π− (k′ π0) and (ii) the diffraction dissociation of pions on nuclei. A new method is given for the selection of the contribution of DD interactions from three prong events. Using this method λDD=(1065±288)m and λDD=(113±13)m are obtained for the mean free path of the diffraction dissociation in emulsion at ∼7 and 17.2 GeV/c, respectively. The possible influence of theDeck effect in the case of three prong events is also investigat