Study of charged particle production in central $p$C and $d$C collisions at a beam momentum of 4.2 GeV/$c$ per nucleon

Abstract

This paper presents a systematic study of charged pion and proton production in inelastic $p^{12}\text{C}$ and $d^{12}\text{C}$ collisions at a beam momentum of 4.2~GeV/$c$ per nucleon as a function of collision centrality, which is characterized by the net charge $Q$ of secondary particles serving as an experimental estimator of the number of participating nucleons. We analyze the average multiplicities and kinematic characteristics of $\pi^{+}$, $\pi^{-}$, and protons, including the mean momentum $\langle p \rangle$, transverse momentum $\langle p_{T} \rangle$, emission angle $\langle \theta \rangle$, and rapidity $\langle y \rangle$. The experimental results are compared in detail with predictions of the FRITIOF model, which provides a satisfactory overall description of the particle multiplicities. A clear centrality dependence is observed: with increasing $Q$, the average momentum of pions decreases while their mean emission angle increases, indicating an enhanced role of secondary intranuclear interactions. These effects are more pronounced in $p\text{C}$ than in $d\text{C}$ collisions. The data presented in this work provide a quantitative benchmark for hadronic transport models in the few-GeV energy range.