Measurements of $\pi^\pm$, $K^\pm$, $p$ and $\bar{p}$ spectra in $^7$Be+$^9$Be collisions at beam momenta from 19$A$ to 150$A$ GeV/$c$ with the NA61/SHINE spectrometer at the CERN SPS

TL;DR

This paper reports measurements of charged pion, kaon, proton, and antiproton spectra in central beryllium-beryllium collisions at various energies, providing insights into particle production and energy dependence in small nuclear systems at CERN SPS.

Contribution

It provides detailed spectra and multiplicities of identified particles in Be+Be collisions across multiple energies, comparing results with models and other collision systems.

Findings

Energy dependence of $K^\\pm$/$\\pi^\\pm$ ratios resembles p+p reactions.

Inverse slope parameters of $K^\\pm$ transverse mass distributions are consistent with previous data.

Results are compared with theoretical models and other collision systems.

Abstract

The NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) studies the onset of deconfinement in hadron matter by a scan of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of $\pi^\pm$, $K^\pm$, $p$ and $\bar{p}$ produced in the 20$\%$ most $central$ $^7$Be+$^9$Be collisions at beam momenta of 19$A$, 30$A$, 40$A$, 75$A$ and 150$A$ GeV/$c$. The energy dependence of the $K^\pm$/$\pi^\pm$ ratios as well as of inverse slope parameters of the $K^\pm$ transverse mass distributions are close to those found in inelastic $p$+$p$ reactions. The new results are compared to the world data on $p$+$p$ and Pb+Pb collisions as well as to predictions of the EPOS, UrQMD, AMPT, PHSD and SMASH models.