K-58+NI-58 AT INCIDENT ENERGIES FROM 1 TO 2 A GEV( PRODUCTION IN THE REACTION NI)

Semi-inclusive triple differential multiplicity distributions of posit ively charged kaons have been measured over a wide range in rapidity a nd transverse mass for central collisions of Ni-58 With Ni-58 nuclei. The transverse mass (m(t)) spectra have been studied as a function of rapidity at a beam energy 1.93 A GeV. The m(t) distributions of K+ mes ons are well described by a single Boltzmann-type function. The spectr al slopes are similar to that of the protons indicating that rescatter ing plays a significant role in the propagation of the kaon. Multiplic ity densities have been obtained as a function of rapidity by extrapol ating the Boltzmann-type fits to the measured distributions over the r emaining phase space. The total K+ meson yield has been determined at beam energies of 1.06, 1.45, and 1.93 A GeV, and is presented in compa rison to existing data. The low total yield indicates that the K+ meso n can not be explained within a hadro-chemical equilibrium scenario, t herefore indicating that the yield does remain sensitive to effects re lated to its production processes such as the equation of state of nuc lear matter and/or modifications to the K+ dispersion relation. (C) 19 97 Elsevier Science B.V.