MULTIFRACTAL ANALYSIS OF INTERMITTENCY AND PHASE-TRANSITIONS IN MULTIPARTICLE DYNAMICS

Multifractal properties of intermittency-like fluctuations as observed in multiparticle collisions are demonstrated, using their description in terms of random cascading models. The f(α) singularity spectrum of these models is explicitly derived and reveals the existence of a spin-glass type transition which can correspond to the physical transient phase produced in such reactions. One finds four classes, with a combination of two different phase transitions. One is analogous to a transition at positive temperature and characterized as a "transition of peaks". The other one with negative temperature is reanalyzed as a "transition of holes". The phase transition diagram depends heavily on the tree structure of the model. The applications of this multifractal scheme to particle multiproduction lead to a practical criterion for the existence and the nature of the new phases one is looking for in particle physics in relation with quantum chromodynamics. © 1990.