Experimental equation of state in proton-proton and proton-antiproton collisions and phase transition to quark gluon plasma

TL;DR

This paper derives approximate equations of state from experimental data in proton collisions, indicating a possible crossover to quark-gluon plasma at specific particle density ranges.

Contribution

It introduces a method to estimate thermodynamic quantities from collision data and suggests evidence for a phase transition to quark-gluon plasma.

Findings

Crossover from hadron gas to quark-gluon plasma likely begins at dN/deta ≈ 6.

Crossover completes at dN/deta ≈ 24.

Results align with theoretical predictions for phase transition.

Abstract

We deduce approximate equations of state from experimental measurements in proton-proton and proton-antiproton collisions. Thermodynamic quantities are estimated combining the measure of average transverse momentum <pt> vs pseudorapidity density dN/deta with the estimation of the interaction region size from measures of Bose Einstein correlation, or from a theoretical model which relates dN/deta to the impact parameter. The results are very similar to theory predictions in case of crossover from hadron gas to quark gluon plasma. According to our analysis, the possible crossover should start at dN/deta about 6 and end at dN/deta about 24.