CHARGE CORRELATIONS AND TRANSVERSE-MOMENTA OBSERVED IN MULTIFRAGMENTATION OF 1 GEV NUCLEON AU PROJECTILES

We have investigated the fragmentation of Au-197 projectiles at 0.85 t o 1 GeV/nucleon in collisions with targets (CH2)n, C, and Pb. Using pl astic nuclear track detectors all projectile fragments with charge 6 g reater-than-or-equal-to Z(F) greater-than-or-equal-to 77 produced in a collision were observed in coincidence. The combination of C and (CH2 )n data allows us to extract the hydrogen component in measured distri butions by the use of the statistical subtraction method. Our data sho w a target dependence of the multifragmentation process which indicate s a nonequilibrated source of the fragments and/or the influence of th e target nucleus on the relation between size and excitation energy of the spectator. In comparison to the prediction of the statistical mod el, the transverse momentum dispersions are enhanced with a dominant c ontribution by Coulomb repulsion between the fragments. Based on the s um of transverse momentum vectors of all fragments we conclude that mu ltifragmentation is observed in collisions with a large momentum and e nergy transfer to the prefragment. Correlations in the azimuthal emiss ion angles of the fragments are caused by mutual repulsion and momentu m conservation. The idea that a liquid-gas phase transition of nuclear matter is the origin of multifragmentation is supported by our observ ations.