Quark-gluon plasma connected to finite heat bath

We derive entropy formulas for finite reservoir systems, S-q, from universal thermostat independence and obtain the functional form of the corresponding generalized entropy-probability relation. Our result interprets thermodynamically the subsystem temperature, T-1, and the index q in terms of the temperature, T, entropy, S, and heat capacity, C of the reservoir as T-1 = T exp(-S/C) and q = 1-1/C. In the infinite C limit, irrespective of the value of S, the Boltzmann-Gibbs approach is fully recovered. We apply this framework for the experimental determination of the original temperature of a finite thermostat, T, from the analysis of hadron spectra produced in high-energy collisions, by analyzing frequently considered simple models of the quark-gluon plasma.