Improved Direct Measurement of $A_b$ and $A_c$ at the $Z^0$ Pole Using a Lepton Tag

Abstract

The parity violation parameters $A_b$ and $A_c$ of the $Zb\bar{b}$ and $Zc\bar{c}$ couplings have been measured directly, using the polar angle dependence of the polarized cross sections at the $Z^0$ pole. Bottom and charmed hadrons were tagged via their semileptonic decays. Both the electron and muon analyses take advantage of new multivariate techniques to increase the analyzing power. Based on the 1993-98 SLD sample of 550,000 $Z^0$ decays produced with highly polarized electron beams we measure $A_b=0.919\pm 0.030_{stat}\pm 0.024_{syst}$, and $A_c=0.583\pm 0.055_{stat}\pm 0.055_{syst}$.

14 pages, 2 figures, to be submitted to Physical Review Letters. Version two contains changes to meet suggestions of reviewers. Version three corrects a problem in Figure 2 that I hadn't noticed

References in corpus (2)

• A High-Precision Measurement of the Left-Right Z Boson Cross-Section Asymmetry
• Precise measurement of the b-quark fragmentation function in Z0 boson decays

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• Triple product correlations in top squark decays
• CP asymmetries with Longitudinal and Transverse Beam Polarizations in Neutralino Production and Decay into the Z^0 Boson at the ILC
• CP asymmetries in chargino production and decay: the three-body decay case
• CP asymmetries in scalar bottom quark decays
• Experimental Precision Tests for the Electroweak Standard Model
• Impact of CP phases on SUSY particle production and decays