Composite-particle emission in the reaction p plus Au at 2.5 GeV

The emission of composite-particles is studied in the reaction p + Au at E-p = 2.5 GeV, in addition to neutrons and protons. Most particle energy spectra feature an evaporation spectrum superimposed on an exponential high-energy, non-statistical component. Comparisons are first made with the predictions by a two-stage hybrid reaction model, where an intra-maclear cascade (INC) simulation is followed by a statistical evaporation process. The high-energy proton component is identified as product of the fast pre-equilibrium INC, since it is rather well reproduced by the INCL2.0 intranuclear cascade calculations simulating the first reaction stage. The low-energy spectral components are well understood in terms of sequential particle evaporation from the hot nuclear target remnants of the fast INC. Evaporation is modeled using the statistical code GEMINI. Implementation of a simple coalescence model in the INC code can provide a reasonable description of the multiplicities of high-energy composite particles such as H2-3 and He-3. However, this is done at the expense of H which then fails to reproduce the experimental energy spectra. (C) 2002 Elsevier Science B.V. All rights reserved.