Next: Selection of Specific Up: Event Selection Previous: Selection Criteria

Selection Efficiency and Backgrounds

The event selection efficiency and background contamination were estimated using Monte Carlo. The production of tau-pair events at the resonance was simulated using the KORALZ 3.8[10] Monte Carlo generator. The same program was used to generate muon-pair events, while wide-angle Bhabha scattering, two-photon interactions, and final states were produced using the generators described in Refs. [11], [12], and [13], respectively. All these Monte Carlo data samples were subjected to the SLD detector simulation based on the GEANT 3.15[14] program and to the above event selection. The SLD trigger was also simulated in the Monte Carlo.

We determine a tau-pair event selection efficiency of , where the largest loss is due to the solid angle coverage of the CDC. The trigger efficiency is found to be , and the result is an overall selection efficiency of . Based on these estimates, the measured integrated luminosity, and the branching fraction, we expect a final tau sample of events, including backgrounds. This is consistent with the 1671 tau-pair candidate events selected in the data. From the fraction of Monte Carlo background events which survive the selection requirements, the purity of the tau sample is estimated to be . The accuracy of these estimates was checked by comparing data and Monte Carlo distributions for various quantities used in the event selection.

Mon Sep 11 11:36:55 PDT 1995