Anti-nuclei and nuclei production in Pb+Pb collisions at CERN SPS energies

TL;DR

This paper reports on the production of light nuclei and anti-nuclei in lead-lead collisions at CERN SPS energies, analyzing their spectra, ratios, and yields to understand the underlying particle production mechanisms.

Contribution

It provides new measurements of 3He, tritons, and anti-deuterons across various energies, and compares these results with statistical models and coalescence parameters.

Findings

Weak energy dependence of t/3He ratio at SPS energies.

Total 3He yield well described by a statistical hadron gas model.

Gradual decrease of coalescence parameter B3 with increasing collision energy.

Abstract

We present new results on production of 3He and t obtained by the NA49 experiment in 20A, 30A, 40A and 80A GeV central Pb+Pb collisions at the CERN SPS. Transverse mass spectra and rapidity distributions for clusters measured over a large phase space domain are discussed. We observe a weak dependence of the mid-rapidity t/3He ratio on collision energy at SPS. The energy dependence of the total yield for 3He is remarkably reproduced by a statistical hadron gas model. A gradual decrease of the coalescence parameter B3 for 3He with $\sqrt {s_{NN}}$ is observed.In addition, a measurement of the yield of anti-deuterons in Pb+Pb reactions at SPS's top energy of $\sqrt {s_{NN}}$ = 17.2 GeV is presented.