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K. Abe et al

Publications and source records attributed to K. Abe et al.

6 recordsLinked to original sources
arXiv2002

Studies of the Decay B+- -> D_CP K+-

We report studies of the decay B+- -> D_CP K+-, where D_CP denotes neutral D mesons that decay to CP eigenstates. The analysis is based on a 29.1/fb data sample of collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric e+ e- storage ring. Ratios of branching fractions of Cabibbo-suppressed to Cabibbo-favored processes involving D_CP are determined to be B(B- -> D_1 K-)/B(B- -> D_1 pi-)=0.125 +- 0.036 +- 0.010 and B(B- -> D_2 K-)/B(B- -> D_2 pi-)=0.119 +- 0.028 +- 0.006, where indices 1 and 2 represent the CP=+1 and CP=-1 eigenstates of the D0 - anti D0 system, respectively. We also extract the partial rate asymmetries for B+- -> D_CP K+-, finding A_1 = 0.29 +- 0.26 +- 0.05 and A_2 = -0.22 +- 0.24 +- 0.04.

hep-ex↗
arXiv1998

An Improved Test of the Flavor Independence of Strong Interactions

We present an improved comparison of the strong coupling of the gluon to light (q_l=u+d+s), c, and b quarks, determined from multijet rates in flavor-tagged samples of hadronic Z0 decays recorded with the SLC Large Detector at the SLAC Linear Collider between 1993 and 1995. Flavor separation among primary q_l q_l-bar, c c-bar, and b b-bar final states was made on the basis of the reconstructed mass of long-lived heavy-hadron decay vertices, yielding tags with high purity and low bias against >= 3-jet final states. We find alpha_s^c/alpha_s^uds = 1.036+-0.043 (stat) +0.041-0.045 (syst) +0.020-0.018 (theory) and alpha_s^b/alpha_s^uds = 1.004+-0.018 (stat) +0.026-0.031 (syst) +0.018-0.029 (theory).

hep-ex↗
arXiv1997

Measurement of the B Hadron Energy Distribution in Z0 Decays

We have measured the B hadron energy distribution in Z0 decays using a sample of semi-leptonic B decays recorded in the SLD experiment at SLAC. The energy of each tagged B hadron was reconstructed using information from the lepton and a partially reconstructed charm-decay vertex. We compared the scaled energy distribution with several models of heavy quark fragmentation. The average scaled energy of primary B hadrons was found to be = 0.716 +- 0.011 (stat.) +0.022 -0.021 (syst.).

hep-ex↗
arXiv1997

Measurement of Leading Particle Effects in Decays of Z0 Bosons into Light Flavors

We present evidence for leading particle production in hadronic decays of the Z0 boson to light-flavor jets. A polarized electron beam was used to tag quark and antiquark jets, and a vertex detector was employed to reject heavy-flavor events. Charged hadrons were identified with a Cherenkov ring imaging detector. In the quark jets, more high-momentum p, Lambda, K-, and anti-K*0 were observed than their antiparticles, and vice versa for antiquark jets, providing direct evidence that the higher-momentum particles in jets are more likely to carry the primary quark or antiquark from the Z0 decay, and that s-s(bar) production is suppressed in fragmentation.

hep-ex↗
arXiv1995

Measurements of the Proton and Deuteron Spin Structure Function g2 and Asymmetry A2

We have measured proton and deuteron virtual photon-nucleon asymmetries A2p and A2d and structure functions g2p and g2d over the range 0.03<x<0.8 and 1.3<Q2<10 (GeV/c)2 by inelastically scattering polarized electrons off polarized ammonia targets. Results for A2 are significantly smaller than the positivity limit sqrt(R) for both targets. Within experimental precision, the g2 data are well-described by the twist-2 contribution g2WW. Twist-3 matrix elements have been extracted and are compared to theorectical predictions.

hep-ex↗