227 research outputs found
A Search for Jet Handedness in Hadronic Decays
We have searched for signatures of polarization in hadronic jets from decays using the ``jet handedness'' method. The polar angle
asymmetry induced by the high SLC electron-beam polarization was used to
separate quark jets from antiquark jets, expected to be left- and
right-polarized, respectively. We find no evidence for jet handedness in our
global sample or in a sample of light quark jets and we set upper limits at the
95% C.L. of 0.063 and 0.099 respectively on the magnitude of the analyzing
power of the method proposed by Efremov {\it et al.}Comment: Revtex, 8 pages, 2 figure
Measurement of the Charged Multiplicities in b, c and Light Quark Events from Z0 Decays
Average charged multiplicities have been measured separately in , and
light quark () events from decays measured in the SLD experiment.
Impact parameters of charged tracks were used to select enriched samples of
and light quark events, and reconstructed charmed mesons were used to select
quark events. We measured the charged multiplicities:
,
, from
which we derived the differences between the total average charged
multiplicities of or quark events and light quark events: and . We compared
these measurements with those at lower center-of-mass energies and with
perturbative QCD predictions. These combined results are in agreement with the
QCD expectations and disfavor the hypothesis of flavor-independent
fragmentation.Comment: 19 pages LaTex, 4 EPS figures, to appear in Physics Letters
A Measurement of alpha-s from jet rates at the Z0 resonance
We have determined the strong coupling alpha(s) from measurements of jet rates in hadronic decays of Z0 bosons collected by the SLD experiment at SLAC. Using six collinear and infrared safe jet algorithms we compared our data with the predictions of QCD calculated up to second order in perturbation theory, and also with resummed calculations. We find alpha(s)(M(Z)2)=0.118+/-0.002(stat)+/-0.003(syst) +/-0.010 (theory), where the dominant uncertainty is from uncalculated higher order contributions
Measurement of alpha-s from energy-energy correlations at the Z0 resonance
We have determined the strong coupling alpha-s from a comprehensive study of
energy-energy correlations (EEC) and their asymmetry (AEEC) in hadronic decays
of Z0 bosons collected by the SLD experiment at SLAC. The data were compared
with all four available predictions of QCD calculated up to O(alpha-s**2) in
perturbation theory, and also with a resummed calculation matched to all four
of these calculations. We find large discrepancies between alpha-s values
extracted from the different O(alpha-s**2) calculations. We also find a large
renormalization scale ambiguity in alpha-s determined from the EEC using the
O(alpha-s**2) calculations; this ambiguity is reduced in the case of the AEEC,
and is very small when the matched calculations are used. Averaging over all
calculations, and over the EEC and AEEC results, we obtain
alpha-s(MZ)=0.124+0.003-0.004(exp.) +-0.009(theory).Comment: 37, SLAC-PUB-645
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