arXiv subjects

Koya Abe

Publications and source records attributed to Koya Abe.

3 recordsLinked to original sources

arXiv2003

First measurement of the double-inclusive B/Bbar hadron energy distribution in e+e- annihilations, and of angle-dependent moments of the B and Bbar energies

We have made the first measurement of the double-inclusive B/Bbar energy distribution in e+e- annihilations, using a sample of 400,000 hadronic Z0 decay events recorded in the SLD experiment at SLAC between 1996 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector were used to reconstruct B/Bbar decay vertices with high efficiency and purity, and to provide measurements of the kinematic quantities used to calculate the B energies in this novel technique. We measured the B/Bbar energies with good efficiency and resolution over the full kinematic range. We measured moments of the scaled energies of the B and Bbar hadrons vs. the opening angle between them. By comparing these results with perturbative QCD predictions we tested the ansatz of factorisation in heavy-quark production. A recent next-to-leading order calculation reproduces the data.

hep-ex↗

arXiv2002

Measurement of the b-quark fragmentation function in Z0 decays

We present a measurement of the b-quark inclusive fragmentation function in Z0 decays using a novel kinematic B-hadron energy reconstruction technique. The measurement was performed using 350,000 hadronic Z0 events recorded in the SLD experiment at SLAC between 1997 and 1998. We compared the sacled B-hadron energy distribution with models of b-quark fragmentation and with several ad hoc functional forms. A number of models and functions are excluded by the data. The average scaled energy of weakly-decaying B hadrons was measured to be = 0.709 +-0.003 (stat) +-0.003 (syst) +-0.002 (model).

hep-ex↗

arXiv2000

First symmetry tests in polarized Z0 decays to b bbar g

We have made the first direct symmetry tests in the decays of polarized Z0 bosons into fully-identified b bbar g states, collected in the SLD experiment at SLAC. We searched for evidence of parity violation at the b bbar g vertex by studying the asymmetries in the b-quark polar- and azimuthal-angle distributions, and for evidence of T-odd, CP-even or odd, final-state interactions by measuring angular correlations between the three-jet plane and the Z0 polarization. We found results consistent with Standard Model expectations, and set 95% C.L. limits on anomalous contributions.

hep-ex↗