Production of deuterium, tritium, and $^3$He in central Pb+Pb collisions at 20A, 30A, 40A, 80A, and 158A GeV at the CERN SPS

TL;DR

This study measures the production of light nuclei like deuterium, tritium, and helium-3 in central lead-lead collisions at various energies at CERN SPS, analyzing spectra, ratios, and coalescence parameters to understand nuclear formation mechanisms.

Contribution

It provides new experimental data on light nuclei production across multiple energies and compares results with statistical and coalescence models, advancing understanding of nuclear coalescence in heavy-ion collisions.

Findings

Yields consistent with statistical model predictions.

Coalescence parameters vary with transverse mass and energy.

Phase-space distributions support coalescence as a formation mechanism.

Abstract

Production of $d$, $t$, and $^3$He nuclei in central Pb+Pb interactions was studied at five collision energies ($\sqrt{s_{NN}}=$ 6.3, 7.6, 8.8, 12.3, and 17.3 GeV) with the NA49 detector at the CERN SPS. Transverse momentum spectra, rapidity distributions, and particle ratios were measured. Yields are compared to predictions of statistical models. Phase-space distributions of light nuclei are discussed and compared to those of protons in the context of a coalescence approach. The coalescence parameters $B_2$ and $B_3$, as well as coalescence radii for $d$ and $^3$He were determined as a function of transverse mass at all energies.