LONGITUDINAL PHASE-SPACE OF MULTIPARTICLE FINAL-STATES IN HIGH-ENERGYHADRON-HADRON COLLISIONS

The highly anisotropic phase space (known as longitudinal phase space) of multiparticle final states in high energy hh collisions is studied in detail. It is pointed out that the anisotropy of phase space shoul d manifest itself not only in the dramatic difference in magnitude bet ween the average transverse and longitudinal momenta, but also in the anisotropy of dynamical fluctuations in the two directions. It means t hat the particle distribution in phase space has the property of selfa ffine fractal. A method for experimentally testing the selfaffine frac tality and measuring its characteristic parameterHurst exponent is giv en. In addition, the correlation between the degree of longitudinal fr actality and the magnitude of average transverse momentum is discussed . A new characteristic quantity- average transverse momentum per event - for de scribing the dynamical property of an event (hard, soft or ul trasoft) is proposed. A comparison of the results with experimental da ta is given.