Adiabatic expansion, local equilibrium and extended Maxwell distribution for fire-ball to describe multiple particle production (II)

Abstract

The model of multiple particle production in [A. Ohsawa, Int. J. Mod. Phys. A (2023) 2350166.] assumes a fire-ball of a gas, consisting of grains, with the adiabatic and one-dimensional expansion, local equilibrium at the final state and the extended Maxwell distribution for the energy distribution of the grains. There are small and large [Formula: see text] (transverse momentum) processes for grains. The grain produces several hadrons to be observed in the experiments at the final state. The model describes well the pseudo-rapidity density distributions and the [Formula: see text] distributions at various incident energies. In this paper it is shown that the model reproduces well the incident energy dependences of [Formula: see text] (the average [Formula: see text] of produced particles), [Formula: see text] (the charged multiplicity) and [Formula: see text] (the pseudo-rapidity density at [Formula: see text]). Furthermore it is shown that the inelasticity is almost energy-independent and [Formula: see text] in the energy region of [Formula: see text][Formula: see text]GeV, and that the Feynman scaling law is violated. The model indicates that the fire-ball satisfies the conditions for quark-gluon plasma, that the grains of the large [Formula: see text] process may be identified with jets, and that [Formula: see text]’s of the grains in the large [Formula: see text] process are due to mutual collision of the grains during the one-dimensional expansion.