LONGITUDINAL PHASE-SPACE PLOTS OF MULTIPARTICLE HADRON COLLISIONS AT HIGH ENERGY

The accurate study of collisions with more than two particles in the final state is greatly hampered by the high dimensionality of the phase space in which the distribution of final states must be investigated. Taking advantage of the fact that in hadron collisions at high energy all transverse momenta remain generally small, we separate phase space into its longitudinal and transverse parts, and we show that for a n-particle collision the longitudinal phase-space distribution reduces to a manifold of dimension n-2. We study the main properties of longitudinal phase-space plots, the way in which relativistically invariant subenergies and momentum transfers vary along them, as well as the qualitative properties of reggeized multiperipheral amplitudes. The longitudinal phase-space plot is parametrized by new angular variables ω1,...ωn-2 and the interest of plotting events against them is demonstrated. The paper ends with a new method for Monte Carlo integration of phase-space integrals. © 1969.