Evidence for double diffractive excitation in pp → (pπ+ π−) + X at the CERN ISR and test of factorization

Abstract In a magnetic spectrometer experiment at the CERN Intersecting Storage Rings (ISR), evidence is obtained for the existence of double diffractive excitation in the reaction pp → ( pπ + π − ) + X at 〈 p t 2 〉 = 0.03 GeV 2 and S = 53 GeV . X is observed to be a multi-body low-mass system 12% of the time, in agreement with the same rate observed in pp → p + X.