arXiv subjects

Kenji Abe

Publications and source records attributed to Kenji Abe.

3 recordsLinked to original sources

arXiv2003

Improved Direct Measurement of the Parity-Violation Parameter A_b Using a Mass Tag and Momentum-Weighted Track Charge

We present an improved direct measurement of the parity-violation parameter A_b in the Z boson-b quark coupling using a self-calibrating track-charge technique applied to a sample enriched in Z -> b b-bar events via the topological reconstruction of the B hadron mass. Manipulation of the SLC electron-beam polarization permits the measurement of A_b to be made independently of other Z-pole coupling parameters. From the 1996-98 sample of 400,000 hadronic Z decays, produced with an average beam polarization of 73.4%, we find A_b = 0.906 +/- 0.022(stat.) +/- 0.023(syst.).

hep-ex↗

arXiv2002

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

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} $.

hep-ex↗

arXiv1999

Precise measurement of the b-quark fragmentation function in Z0 boson decays

We have developed a new technique for inclusive reconstruction of the energy of B hadrons. The excellent efficiency and resolution of this technique allow us to make the most precise determination of the b-quark fragmentation function, using e+e- -> Z0 decays recorded in the SLD experiment at SLAC. We compared our measurement with the predictions of a number of fragmentation models. We excluded several of these models and measured the average scaled energy of weakly-decaying B hadrons to be =0.714+-0.005(stat)+-0.007(syst) +-0.002(model dependence).

hep-ex↗