2019/10/21 by E. É. Kolomeitsev, Kolomeitsev, E. E., D. N. Voskresensky +3 · 1 citation
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Nuclear Theory (nucl-th) #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.1910.09334
openalex publication_date 2019/10/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the behavior of the non-ideal pion gas with the dynamically fixed number of particles, formed on an intermediate stage in ultra-relativistic heavy-ion collisions. The pion spectrum is calculated within the self-consistent Hartree approximation. General expressions are derived for cross-covariances of the number of various particle species in the pion gas of an arbitrary isospin composition. The behavior of the cross-variances is analyzed for the temperature approaching from above the maximal critical temperature of the Bose-Einstein condensation for the pion species a=±,0, i.e. for T>max T\rm cra. It is shown that in case of the system with equal averaged numbers of isospin species, the variance of the charge, Q=N+-N-, diverges at T→ T\rm cr=T\rm cra, whereas variances of the total particle number, N=N+ + N- + N0, and of a relative abundance of charged and neutral pions, G=(N++N-)/2 - N0, remain finite in the critical point. Then fluctuations are studied in the pion gas with small isospin imbalance 0maxT\rm cra, which prove to be strongly dependent on the isospin composition of the system, whereas the variances of N and G are found to be independent on the isospin imbalance up to the term linear in G/N and Q/N.