# Light fragment production at CERN Super Proton Synchrotron

## TL;DR

This study analyzes light fragment production in Pb+Pb collisions at CERN SPS energies using a three-fluid dynamics model with coalescence, finding that models with deconfinement transition better reproduce rapidity distributions of light nuclei.

## Contribution

It introduces a combined 3FD and coalescence model to describe light fragment production, highlighting the importance of deconfinement transition scenarios.

## Key findings

- Deconfinement transition models better reproduce rapidity distributions.
- Transverse-mass spectra of helium-3 do not match experimental data well.
- Coalescence coefficients may need to depend on temperature or momentum.

## Abstract

Recent data on the deutron and $^3$He production in central Pb+Pb collisions at the CERN Super Proton Synchrotron (SPS) energies measured by the NA49 collaboration are analyzed within the model of the three-fluid dynamics (3FD) complemented by the coalescence model for the light-fragment production. The simulations are performed with different equations of state---with and without deconfinement transition. It is found that scenarios with the deconfinement transition are preferable for reproduction rapidity distributions of deuterons and $^3$He, the corresponding results well agree with the experimental data. At the same time the calculated transverse-mass spectra of $^3$He at midrapidity do not that nice agree with the experimental data. The latter apparently indicates that coalescence coefficients should be temperature and/or momentum dependent.