Rapidity-gap separation and study of single-diffraction dissociation in pp collisions at 12 and 24 GeV/c☆

Abstract An event-by-event separation of the single-diffractive component in the inclusive reaction p + p → p + X is attempted with our 12 and 24 GeV/ c bubble-chamber data, using a method involving largest rapidity gaps. The method yields a (non-strange) single-diffraction cross section of about 7 mb at both energes, dominated by two and four prongs. For the diffractive component the recoil mass distribution d σ /d M X 2 shows a sharp peak near M X 2 = 2 GeV 2 at both energies, with a long tail that broadens significantly with increasing energy. This shape is reasonably well described by the diffractive terms of a triple-Regge fit to the full pp data. The slope parameter of the diffractive t distribution shows a precipitous drop with increasing M X 2 , levelling off abruptly at M X 2 ≈ 3 GeV 2 . The mean charged multiplicity of the diffractive system appears to be linear in log M X 2 and independent of s .