Semi-Leptonic Charged D Meson Decays in 800 GEV P-Emulsion Interactions.

Results from experiment 653 at FNAL on semi-muonic D^+/- decays are presented. The analysis restricts itself to the study of electronically reconstructed vertices outside the emulsion target. This requirement eliminates the problem of secondary interactions mimicking a decay. Only vertices that contain three charged tracks, where one is identified as a muon, are considered. Using the minimum mass method on these data and invoking a maximum likelihood fit, results in a partial width ration D^+/- to K^mppi^ +/-mu^+/-nu_{mu } to D^+/- to K^mppi^ +/-mu^+/-pi^{0 }nu_{mu} of 0.28 _sp{-0.16}{+0.20}. This implies a large five body muonic decay rate. The resonant fraction (K^{ * 0}(892) to K^mp pi_sp{non-res}+/-) in this semi-muonic sample was determined to be 0.65 _sp{-0.18}{+0.20} suggesting a non-negligible S-wave Kpi component. This is in good agreement with other experiments where the study involved semi-electronic decays. A polarization study of the K^ {* 0}(892) sample allowed the determination of a lower limit on the longitudinal to transverse partial width ratio. The K^{* 0} (892)s produced in D^+/- semi-muonic decays are longitudinally polarized with {tau_{L}overtau _{T}} >=q 0.8 at 90% C.L. which is consistent with the quark model prediction of {Gamma_{L }overGamma_{T}} ~ 1.