van der Waals Interactions in Hadron Resonance Gas: From Nuclear Matter to Lattice QCD

Understand

An extension of the ideal hadron resonance gas (HRG) model is constructed which includes the attractive and repulsive van der Waals (VDW) interactions between baryons.

• This VDW-HRG model yields the nuclear liquid-gas transition at low temperatures and high baryon densities.
• The VDW parameters $a$ and $b$ are fixed by the ground state properties of nuclear matter, and the temperature dependence of various thermodynamic observables at zero chemical potential are calculated within VDW-HRG model.
• Compared to the ideal HRG model, the inclusion of VDW interactions between baryons leads to a qualitatively different behavior of second and higher moments of fluctuations of conserved charges, in particular in the so-called crossover region $T\sim 140 - 190$ MeV.