A Measurement of R(b) using a vertex mass tag

We report a new measurement of Rb = Gamma(Z0->b-bbar) / Gamma(Z0->hadrons) using a double tag technique, where the b hemisphere selection is based on the reconstructed mass of the B hadron decay vertex. The measurement was performed using a sample of 130k hadronic Z0 events, collected with the SLD at the SLC. The method utilizes the 3-D vertexing abilities of the CCD pixel vertex detector and the small stable SLC beams to obtain a high b-tagging efficiency and purity. We obtain Rb=0.2142+/-0.0034(stat.)+/-0.0015(syst.)+/-0.0002(R_c).

Note:

11 pages including 3 eps files

electron positron: colliding beams
electron positron: annihilation
Z0: electroproduction
Z0: hadronic decay
Z0: branching ratio
bottom: pair production
particle identification: bottom
semiconductor detector: vertex
SLD
experimental results

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