A study of the asymmetry in the photoproduction of D meson(*+) and D meson(*-) at photon energies of 40 to 160 GeV

Evidence for an asymmetry in the photoprodurtion of D’+ and D'- at photon energies of 40-160 GeV was found in Fermilab experiment E51G. The experiment, studied high energy yp interactions using the Tagged Photon Spectrometer, consisting of a sophisticated recoil detector to study the target fragments, and a large acceptance forward spectrometer. The charged D* signal was detected in the decay channel D*+ —> D °~ +, with subsequent- decay of the D n via the decay modes D° - A - t t + . D ° - 7 v '- - + - + - - . £>° - A i V - - . or D° Using the unique capabilities of the recoil detectorto accurately indicate dilFracfive processes, the first direct measurement of the asymmetry (in the form of the ratio of anti-charmed to charmed D* mesons) for purely non-diffractive processes was found to be 1.3S ± 0.2S. The data also showed no indication of asymmetric production for purely diffractive events. The asymmetry in the non-diffractive component, of signal was interpreted as evidence for associated production of A* D*“ , which was consistent with a n earlier E516 report for the direct observation of associatively produced A(e)+. Finally, the results were seen as consistent with previously reported photoproduction experiments conducted at different photon energy ranges.Ph.D