Remarks on the thermodynamical model of strong interactions

Abstract

The thermodynamical model of strong interactions is described with the emphasis on aspects neglected in previous papers and on its relation to other recent developments and proposals in high-energy physics. Kinematical aspects: “limiting fragmentation”. The pure thermodynamical part: how to incorporate strong interactions in phase space; passing from phase space to thermodynamics (canonical ensemble); attempt to incorporate the whole of strong interactions (bootstrap, duality); the consequence (exponential hadron-mass spectrum, universal highest temperature T o ≈ 160 MeV, Planck-type momentum spectra, limited transverse momenta, Poisson-like multiplicity distributions). A glance at Feynman's ideas: exclusive experiments (for examples A + B → A′ + B′ at forward and large angles); inclusive experiments (one-particle distributions; equivalence of “limiting fragmentation” with Feynman's predictions and with energy independence of the velocity weight functions of the thermodynamical model; are partons fireballs? an approximate scaling law for differential production cross sections). Main results of the thermodynamical model: transverse momenta in very high-energy collisions; can the transverse-momentum distribution be derived from the uncertainty relation applied to the interaction volume? Complications arising from applying the model to a variety of experimental situations. Detailed examples: differential cross sections, invariant-mass distributions, multiplicities, transverse momentum as a function of mass and longitudinal momentum, log tan 1 2 Θ ∗− distribution . Philosophy: the case for bootstrap and non-existence of “truly elementary” material building blocks. Symmetries, not material particles are fundamental.