Pion diffraction dissociation into five pions at 16 GeV/c

In π+-p interactions at 16 GeV/c, evidence is obtained for the existence of the diffractive dissociation of the pion into five pions (π → 5π), and possibly also for π → 7π, on the basis of the Feynman x distribution of the slowest pion. Cross sections for the five-pion diffractive component are estimated for the π+ and the π- experiments using two methods. In a selected event sample characterized by the dominance of diffractive production of five-pion systems, an average rho0(770) multiplicity of 1.75+-0.20 was measured, indicating rho0rho0π contributions in at least 75% of the events. The slope of the four-momentum transfer distribution of the five-pion systems was found to be similar to that of diffractively produced three-pion systems of the same mass. The results are compared with those reported for five-pion systems coherently produced on a deuteron target. (Auth.)