A statistical mechanics framework for multi-particle production in high   energy reactions
  We deduce the particle distributions in particle collisions with multihadron-production in the framework of mechanical statistics. They are derived as functions of x, P_T^2 and the rest mass of different species for a fixed total number of all produced particles, inelasticity and total transverse energy. For P_T larger than the mass of each particle we get the behaviour \frac{dn_i}{dP_T} \sim \sqrt{P_T} e^{-\frac{P_T}{T_H}} Values of <P_T>_\pi, <P_T>_K, and <P_T>_{\bar{p}} in agreement with experiment are found by taking T_H=180MeV (the Hagedorn temperature). 
F. Buccella and L. Popova