The parameter-free Monte Carlo approach for diffractive dissociation of relativistic oxygen nuclei into four alpha particles in interactions with protons at 3.25GeV/c per nucleon

Abstract

In this paper, we have investigated the processes of formation of four alpha particles in the final state in the reactions [Formula: see text] of diffractive dissociation of oxygen-16 nuclei in interactions with protons at an incident momentum of 3.25[Formula: see text]GeV/[Formula: see text] per nucleon. A Monte Carlo model is proposed to describe the kinematic characteristics of the produced alpha particles. The proposed Monte Carlo model does not have any free parameters. The algorithm of the model takes into account the energetically allowed channels of direct (or cascade) decays of the excited oxygen-16 nuclei into the final four alpha particles. To form the masses of the excited oxygen-16, carbon-12, and beryllium-8 nuclei, the experimental tables of their excitation levels have been used. All decays have been generated isotropically in the rest frame of each unstable nucleus — the excited oxygen-16, carbon-12, and beryllium-8 nuclei. The results of the Monte Carlo model calculations have proved to be in good agreement with distributions of various kinematic characteristics of the final state alpha particles taken from the experiment. The good agreement is reached if, after simulation of the mass of the excited oxygen-16, the energetically allowed decay channel is selected for which the sum of the total energy, released in this channel, and the masses of the four secondary alpha particles turn out to be less, but closest to the mass of the excited oxygen-16 nucleus. At a high level of excitation, there are several channels with the same energy release, which have been generated with equal probabilities.