Small,Large,and Very Large Transverse Momenta in a Unified Hydrodynamical Description.

摘要

Two apparently unrelated effects,viz. the behavior of transverse momentum spectra at ''large'' p/sub T/in p-p collisions and the ''enhancement''of such spectra in p-nucleus collisions,are shown to follow in a natural way from a hydrodynamical model in which the space-time evolution of the system is taken into account. Up to p/sub T/congruent to 5GeV/c a single value (close to u exp 2congruent to exp 1 /sub 7 ) for the velocity of sound in hadronic matter gives a consistent description of all experimental facts. Recent observations at very large p/sub T/ (5to 15GeV/c) require a jump to u exp 2approximately exp 1 /sub 4 ,suggesting the possibility of a phase transition of the second kind. (ERA citation 03:051425)