Production of K exp + K exp - and ppbar Pairs in High Energy Photoproduction

摘要

Using the Fermilab broad-band neutral beam and a multi-particle spectrometer, we have investigated the channels: photon + d -> K exp +- (ppbar) (n, p, d, or X). In K exp + K exp - production, we make precise measurements of the elastic phi photoproduction cross section between 35 GeV and 85 GeV. Between these limits, we see the elastic cross section rise by 25%. At K exp +- masses higher than the phi, we see an enhancement centered at 1.72 +- .02 GeV, with a width of .12 +- .05 GeV. We measure the cross section to be 8.0 +- 2.8 nb/nucleon, with an additional systematic error of 16%. Measurements are made of its production characteristics. The most probable interpretation of this state is a radial excitation of the phi, or phi-prime. Production of ppbar pairs is measured. The ppbar mass spectrum displays no obvious peaks, either in elastic or inelastic photoproduction. Limits are set for previously reported possible states in ppbar electroproduction, which are significantly below the reported cross sections. 57 refs. (ERA citation 10:029069)