Charmed-particle pare and associated production at 20 GeV

A study of the production mechanism of charmed particles photoproduced at 20 GeV in an experiment at the SLAC Hybrid Facility is reported in this thesis. Out of a total of 688,0000 hadronic events, 98 events which had clear evidence of at least one charmed particle were selected for the analysis presented here. The total charm cross section previously reported from this experiment is 62 ± 8-10+15nb. No charmed baryons are fully reconstructed in the sample of visible decays but here is indirect evidence of charmed production. The amount of associated production is measured. Based on events with detected λ, the λc+ → λ branching ratio has been measured to be λc+ → λ (Branching ratio) = 0.29 ± 0.13. A sample of pair production events is identified and used to test the photongluon fusion model of charm production. A Monte Carlo program was used to fit the gluon distribution in the proton using the Lund fragmentation program