부산대학교 도서관

New analyses of baryon spectra in proton-proton and proton-carbon collisions at $\sqrt{s}_\mathrm{_{NN}}=17.3$ GeV, made in the framework of two phenomenological models are presented. The first model in question is the classic Dual Parton Model by Capella and Tran Thanh Van, the second is the Gluon Exchange Model very recently proposed by the authors. For both studies, the usage of modern experimental data from the CERN SPS eliminates several of the most important limitations inherent to earlier studies of this type. In both studies, the standard mechanism of baryon stopping with preservation of the diquark, proposed by Capella and Tran Thanh Van fails to describe the distribution of non-strange baryons in collisions of the projectile proton with {\em more than one} nucleon from the carbon target obtained from experimental data, and the upper limit for the contribution of this mechanism can be established. In both cases, the conclusion is that the projectile diquark must be very often disintegrated. This opens new diagrams not available in proton-proton collisions which lead to the transport of baryon number over long distances in rapidity. The present limitations, and possibility of improvement in both approaches are discussed. The implications of our findings for new measurements are addressed, in particular using antiproton beams.
Comment: 21 pages, 14 figures