The production of charmed mesons D0(over bar), D+/-, and D*+/- is studied in a sample of 478000 hadronic Z decays. The production rates are measured to be GAMMA(Z -> D*+/- X)/GAMMA(had) = 0.187 +/- 0.015 (exp.) +/- 0.013 (BR), GAMMA(Z -> D+/- X) = 0.251 +/- 0.026 (exp.) +/- 0.025 (BR), GAMMA(Z -> D0(bar) X)/GAMMA(had) = 0.518 +/- 0.052 (exp.) +/- 0.035 (BR), where the errors from this analysis are separated from those coming from the D branching ratios (BR). The D *+/- momentum distribution is extracted separately for Z -> c cbar and Z --> b bbar events with the help of event shape variables. It is consistent with the prediction of the JETSET Monte Carlo program after adjustment of the charm fragmentation function. Constraining the shape of the Z -> b bbAR contribution, the average fraction of the beam energy taken by a D* meson produced in the fragmentation of a charm quark is extracted by a parametric fit to be <X_E>_c= 0.495 +/- 0.011 +/- 0.007. Evidence for D**0 (D1(2420)0 and/or D2*(2460)0) production is found in the D*+/- pi-/+ channel, accounting for a fraction (18 +/- 5 +/- 2)% of all D*+/- production. The relative production of vector and pseudoscalar mesons is dicussed, together with the possible effects of D** production. The c-quark forward-backward Z-pole asymmetry is determined from that of high momentum D*+/- to be A(FB)0,c = (7.7 +/- 4.4)%.
Production of Charmed Mesons In Z Decays
BATIGNANI, GIOVANNI;CIOCCI, MARIA AGNESE;FERRANTE, ISIDORO;FIDECARO, FRANCESCO;F. FORTI;GIORGI, MARCELLO;MESSINEO, ALBERTO MARIA;RIZZO, GIULIANA;TONELLI, GUIDO EMILIO;G. TRIGGIANI;
1994-01-01
Abstract
The production of charmed mesons D0(over bar), D+/-, and D*+/- is studied in a sample of 478000 hadronic Z decays. The production rates are measured to be GAMMA(Z -> D*+/- X)/GAMMA(had) = 0.187 +/- 0.015 (exp.) +/- 0.013 (BR), GAMMA(Z -> D+/- X) = 0.251 +/- 0.026 (exp.) +/- 0.025 (BR), GAMMA(Z -> D0(bar) X)/GAMMA(had) = 0.518 +/- 0.052 (exp.) +/- 0.035 (BR), where the errors from this analysis are separated from those coming from the D branching ratios (BR). The D *+/- momentum distribution is extracted separately for Z -> c cbar and Z --> b bbar events with the help of event shape variables. It is consistent with the prediction of the JETSET Monte Carlo program after adjustment of the charm fragmentation function. Constraining the shape of the Z -> b bbAR contribution, the average fraction of the beam energy taken by a D* meson produced in the fragmentation of a charm quark is extracted by a parametric fit to beI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.