Measurement of B_d Mixing Using Opposite-side Flavor Tagging

GUSTAVO OTERO Y GARZON, THE DZERO COLLABORATION

PHYSICAL REVIEW D - PARTICLE AND FILDS

Año: 2006 p. 1120021 - 1120027

0556-2821

We report on a measurement of the Bd0 mixing frequency and the calibration of an opposite-side flavor tagger in the D0 experiment. Various properties associated with the b quark on the opposite side of the reconstructed B meson are combined using a likelihood-ratio method into a single variable with enhanced tagging power. Its performance is tested with data, using a large sample of reconstructed Semileptonic B à m D0 X and B à m D* X decays, corresponding to an integrated luminosity of approximately 1 fb-1. The events are divided into groups depending on the value of the combined tagging variable, and an independent analysis is performed in each group. Combining the results of these analyses, the overall effective tagging power is found to be  eD2 = (2.48 ± 0.21+0.08-0.06)%. The measured Bd0 mixing frequency Dmd = 0.506 ± 0.020(stat) ± 0.016(syst) ps-1 is in good agreement with the world average value.