Three-body collisions in Boltzmann-Uehling-Uhlenbeck theory

Abstract

Aiming at a microscopic description of heavy ion collisions in the beam energy region of about $10A$ GeV, we extend the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) transport model by including a relativistic mean field, in-medium baryon-baryon cross sections, and three-body collisions. The model is then compared with experimental data for central Au+Au collisions at $2A\text{\ensuremath{-}}10A$ GeV and central Pb+Pb collisions at $30A$ and $40A$ GeV on the proton rapidity spectra, the midrapidity yields of ${\ensuremath{\pi}}^{+},{K}^{\ifmmode\pm\else\textpm\fi{}},$ and $(\ensuremath{\Lambda}+{\ensuremath{\Sigma}}^{0})$, and the transverse mass spectra of ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ and ${K}^{\ifmmode\pm\else\textpm\fi{}}$. The three-body collisions increase the inverse slope parameters of the hadron ${m}_{\ensuremath{\perp}}$ spectra to good agreement with the data.