Bose-Einstein Condensation of Pions

TL;DR

This paper investigates particle number fluctuations in an ideal pion gas near Bose-Einstein condensation, highlighting how fluctuations dramatically increase near the condensation line, especially at high energies and fixed pion numbers.

Contribution

It provides a detailed analysis of pion fluctuations near Bose-Einstein condensation across different statistical ensembles and identifies observable signals at high collision energies.

Findings

Fluctuations increase dramatically near the condensation line.

Significant signals are observable at fixed total pion number.

Estimates are provided for 70 GeV proton-proton collisions.

Abstract

Particle number fluctuations are studied in the ideal pion gas approaching Bose-Einstein condensation. Two different cases are considered: Bose condensation of pions at large charge densities $\rho_Q$ and Bose condensation at large total densities of pions $\rho_{\pi}$. Calculations are done in grand canonical, canonical and microcanonical ensembles. At high collision energy, in the samples of events with a fixed number of all pions, $N_{\pi}$, one may observe a prominent signal. When $N_{\pi}$ increases the scaled variances for particle number fluctuations of both neutral and charged pions increase dramatically in the vicinity of the Bose-Einstein condensation line. As an example, the estimates are presented for $p+p$ collisions at the beam energy of 70 GeV.