On the possibility of describing the multiplicity distribution of protons in high-energy hadron-nucleus collisions withi
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On the Possibility of Describing the Multiplicity Distribution of Protons in High-Energy Hadron–Nucleus Collisions within a Three-Step Interaction Model K. Olimov* , E. Kh. Bazarov, K. G. Gulamov, V. V. Lugovoi, S. L. Lutpullaev, and V. I. Petrov Institute for Physics and Technology, Fizika–Solntse Research and Production Association, Uzbek Academy of Sciences, ul. G. Mavlyanova 2b, Tashkent, 700084 Republic of Uzbekistan Received May 28, 2007; in final form, August 16, 2007
PACS numbers: 25.10.+s DOI: 10.1134/S1063778808010225
Quantitative estimates of contributions from various proton-production mechanisms are of crucial importance for discriminating between different theoretical approaches. At the present time, it has been reliably established that the production of nucleons (protons and neutrons), which are the lightest fragments of nuclei, occurs at all stages of high-energy hadron–nucleus interactions, which proceeds via a very complicated process involving an intranuclear cascade induced by a projectile particle, the decay of an excited residual nucleus (Fermi breakup) formed following the passage of the intranuclear cascade, and the evaporation of the primary nucleus in peripheral collisions or the deexcitation (similar to evaporation) of multinucleon fragments formed upon the decay of the residual nucleus. Since the momentum spectra of protons formed via various mechanisms overlap (especially in the low-momentum region p 220–250 MeV/c), each of these mechanisms can be isolated only by statistical methods—for example, with the aid of invariant structure functions [1]. However, this approach requires a 100% detection of the protons being considered or introducing correction factors that take into account the loss of fast and slow particles, but which depend greatly on experimental conditions (for example, on the choice of working liquid in the bubble chamber used). As was shown in [2], the multiplicity distributions of protons are also sensitive to contributions of various mechanisms of their production. A simple phenomenological model that takes into account the aforementioned proton-production mechanisms was proposed in [2] for describing the multiplicity distributions of protons in hadron– nucleus collisions at high energies. This model relies *
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on the assumption that proton production via Fermi breakup and evaporation are mechanisms of statistical character and the assumption that the multiplicity distribution of protons has a binomial form. The distribution of protons produced via knockout by a primary particle was calculated according to [3] on the basis of Glauber’s theory of multiple scattering. It should be noted that, in the model proposed in [2], it is sufficient to preset the total (measured) average multiplicity of protons and their multiplicity distribution, whereupon the contributions of various mechanisms are determined as parameters from a fit to the total distribution. The possibility of quantitatively describing the multiplicity distribution of
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