Longitudinal phase space of multiparticle final states in high energy hadron-hadron collisions

The highly anisotropic phase space (known as longitudinal phase space) of multipartide final states in high energy hh collisions is studied in detail. It is pointed out that the anisotropy of phase space should manifest itself not only in the dramatic difference in magnitude between the average transverse and longitudinal momenta, but also in the anisotropy of dynamical fluctuations in the two directions. It means that the particle distribution in phase space has the property of selfaffine fractal. A method for experimentally testing the selfaffine fractality and measuring its cbaracteristic parameterHurst exponent is given. In addition, the correlation between the degree of longitudinal fractality 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 ultrasoft) is proposed. A comparison of the results with experimental data is given.