Helium-3 production from Pb+Pb collisions at SPS energies with the UrQMD model and the traditional coalescence afterburner

Abstract

A potential version of the UrQMD (UrQMD/M) transport model and a traditional coalescence model are combined to calculate the production of ${}^3$He fragments in central Pb+Pb collisions at SPS energies 20-80 GeV/nucleon. It is found that the Lorentz transformation in the afterburner influences visibly the ${}^3$He yield and should be considered in calculations. The rapidity distribution of ${}^3$He multiplicities (including the concave shape) can be described well with UrQMD/M when it stops during t${}_{\mathrm{cut}}$=100$\pm$25 fm$/c$ and the coalescence afterburner with one parameter set of ($R_0$,$P_0$)=(3.8 fm, 0.3 GeV$/$c) is taken into use afterwards.

Comments: 9 pages, 3 figures