Diffraction dissociation of nuclei in 450 GeV/c proton-nucleus collisions

Åkesson, T.; Almehed, S.; Angelis, A. L. S.; Atherton, H.; Aubry, P.; Bartels, H. W.; Beaudoin, G.; Beaulieu, J. M.; Beker, H.; Benary, O.; Bettoni, D.; Bisi, V.; Blevis, I.; Bøggild, H.; Cleland, W.; Clemen, M.; Collick, B.; Corriveau, F.; Dagan, S.; Dederichs, K.; Dell'Uomo, S.; Depommier, P.; Devenish, R. C. E.; Digiacomo, N.; Diliberto, S.; Dodd, J. R.; Dolgoshein, B.; Drees, A.; En'Yo, H.; Erlandsson, B.; Esten, M. J.; Fabjan, C. W.; Faessler, M. A.; Fischer, P.; Fraenkel, Z.; Gaidot, A.; Gibrat Debu, F.; Giubellino, P.; Glässel, P.; Goerlach, U.; Haglund, R.; Hamel, L. A.; van Hecke, H.; Hedberg, V.; Heifetz, R.; Hölscher, A.; Jacak, B.; Jarlskog, G.; Johanson, S.; Kraner, H.; Kroh, V.; Lamarche, F.; Leroy, C.; Lisauer, D.; London, G.; Lorstad, B.; Lounis, A.; Martelli, Filippo; marzari Chiesa, A.; Masera, M.; Mazzoni, M. A.; Mazzucato, E.; Mccubbin, N. A.; Mcgaughey, P.; Meddi, F.; Mjornmark, U.; Muciaccia, M. T.; Muraviev, S.; Murray, M.; Neubert, M.; Nilsson, S.; Olsen, L.; Oren, Y.; Pansart, J. P.; Park, Y. M.; Pfeiffer, A.; Piuz, F.; Polychronakos, V.; Poulard, G.; Price, M.; Rahm, D.; Ramello, L.; Riccati, L.; Romano, G.; Rosa, G.; Sandor, L.; Schukraft, J.; Sekimoto, M.; Seman, M.; Shmeleva, A.; Sidorov, V.; Simone, S.; Sirois, Y.; Sletten, H.; Smirnov, S.; Sondheim, W.; Specht, H. J.; Stumer, I.; Sunier, J. W.; Tcherniatin, V.; Thodberg, H. H.; Thompson, J.; Tikhomirov, V.; Tserruya, I.; Vasseur, G.; Veenhof, R.; Wigmans, R.; Willis, W. J.; Yepes, P.

Diffractive dissociation of nuclei (Be, Al, W) in collisions with 450 GeV/c protons,pA→pX, has been measured with the HELIOS spectrometer at the CERN Super Proton synchrotron. The dependence of the single-diffraction cross-section on the nuclear massA can be parametrized as σSD mb×A 0.35±0.02, showing the peripheral nature of the process. The differential cross-section dσSD=(3.8±0.3)mb ×A 0.35±0.02, is exponential with the slope parameter, increasing from 6.2±0.4 (GeV/c)−2 for beryllium to 7.9±0.5 (GeV/c)−2 for tungsten. The slope parameter also increases with increasing massM X of the diffractively produced state. The rapidity, multiplicity, and transverse-momentum distributions of the particles of the diffractively produced stateX show a longitudinal phase-space population and are remarkably insensitive to the nuclear mass. This, together with theA 1/3 dependence of σSD, suggests that the dominant process of nuclear diffractive excitation is the dissociation of single nucleons.