부산대학교 도서관

The mean values of the momenta and emission angles of charged pions and protons in the laboratory frame are presented both for the total ensemble of interactions between 4.2-GeV/c protons and a carbon nucleus and for six groups of events characterized by different degrees of collision centrality. The distributions with respect to the total and the transverse momentum are presented for the particles being studied, along with the longitudinal-rapidity distributions. Our experimental data are compared with the predictions of the cascade–evaporation model and of two versions of the refined FRITIOF model. It is shown that, as the degree of collision centrality becomes higher, the mean momenta and rapidities of secondaries decrease, the transverse momenta remain virtually unchanged, and the mean angles of particle emission increase. This is consistent with the pattern of particle cascading in nuclei. However, the mean transverse momentum 〈p[sub t]〉 of participant protons that was obtained on the basis of the cascade–evaporation model decreases with increasing degree of collision centrality, in contrast to what is observed in our experiment. A satisfactory description of experimental data is obtained on the basis of the refined FRITIOF model taking into account Δ[sup +] and Δ[sup 0] isobars. The stopping power of carbon nuclei for 4.2-GeV/c protons is also determined.© 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]