Thermo-coalescence model for light nuclei production in relativistic heavy-ion collisions

Abstract We employ a hybrid approach to describe the light nuclei production mechanism where the nucleons are assumed to be thermally produced, and are allowed to form light nuclei using a coalescence prescription. In this approach, we first fit transverse momentum ( $$p_{T}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> </mml:math> ) distribution of nucleons using hydro-inspired boost-invariant Blast-wave model. The extracted parameters are then used to describe the deuteron $$p_{T}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> </mml:math> spectra, along with two additional parameters that characterize the coalescence prescription employed in this study. We refer this combined approach as “thermo-coalescence model” and it is designed to study the deuteron production and describe the experimental measurements. In this work, we analyze the measured $$p_{T}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> </mml:math> distribution of protons and deuterons from Pb–Pb collisions at the ALICE Collaboration at the LHC. We also evaluate the $$p_{T}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> </mml:math> -integrated deuteron yields using this approach and compare with experimental measurements. A Bayesian inference framework is employed to determine the best-fit parameters of the thermo-coalescence model. Finally, we estimate the traditionally used experimental coalescence parameter ( $$B_{A}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>B</mml:mi> <mml:mi>A</mml:mi> </mml:msub> </mml:math> ) within our framework in order to establish a connection between our model and the conventional coalescence approach commonly used to relate experimental data with theoretical descriptions of light nuclei production.