Non-Equilibrium Processes In P Plus Ag Collisions At Gev Energies

The double differential spectra d(2)sigma/d Omega dE of p, d, t, He-3,He-4,He-6, Li-6,Li-7,Li-8,Li-9, Be-7,Be-9,Be-10, and B-10,B-11,B-12 were measured at seven scattering angles, 15.6 degrees, 20 degrees, 35 degrees, 50 degrees, 65 degrees, 80 degrees, and 100 degrees, in the laboratory system for proton induced reactions on a silver target. Measurements were done for three proton energies: 1.2, 1.9, and 2.5 GeV. The experimental data were compared to calculations performed by means of two-step theoretical microscopic models. The first step of the reaction was described by the intranuclear cascade model INCL4.6 and the second one by four different models (ABLA07, GEM2, GEMINI++, and SMM) using their standard parameter settings. Systematic deviations of the data from predictions of the models were observed. The deviations were especially large for the forward scattering angles and for the kinetic energy of emitted particles in the range from about 50 to 150 MeV. This suggests that some important non-equilibrium mechanism is lacking in the present day microscopic models of proton-nucleus collisions in the studied beam energy range.