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Register a new userMeasurement of the Strong Coupling alpha_s from the Four-Jet Rate in e+e- Annihilation using JADE data
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Data from e+e- annihilation into hadrons collected by the JADE experiment at centre-of-mass energies between 14 GeV and 44 GeV are used to study the four-jet event production rate as a function of the Durham jet algorithms resolution parameter ycut. The four-jet rate is compared to QCD next-to-leading order calculations including resummation of large logarithms in the next-to-leading logarithmic approximation. The strong coupling measured from the four-jet rate is as(MZ)=0.1159+-0.0004(stat)+-0.0012(expt)+-0.0024(had)+-0.0007(theo) in agreement with the world average.
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Data from e+e- annihilation into hadrons collected by the JADE experiment at centre-of-mass energies between 14 GeV and 44 GeV were used to study the four-jet rate as a function of the Durham algorithms resolution parameter y_cut. The four-jet rate was compared to a QCD NLO order calculations including NLLA resummation of large logarithms. The strong coupling constant measured from the four-jet rate is alpha_S(M_Z) = 0.1169 +/- 0.0004 (stat) +/- 0.0012 (expt) +/- 0.0021 (had) +/- 0.0007 (theo), alpha_S(M_Z) = 0.1169 +/- 0.0026 (total error) in agreement with the world average.
We describe a measurement of the strong coupling alpha_S(m_Z) from the 3-jet rate in hadronic final states of e+e- annihilation recorded with the JADE detector at centre-of-mass energies of 14 to 44 GeV. The jets are reconstructed with the Durham jet clustering algorithm. The JADE 3-jet rate data are compared with QCD predictions in NNLO combined with resummed NNLA calculations. We find good agreement between the data and the prediction and extract alpha_S(m_Z)= 0.1199 +/- 0.0010(stat.) +/- 0.0021(exp.) +/- 0.0054(had.) +/- 0.0007(theo.).
Data from e+e- annihilation into hadrons collected by the JADE experiment at centre-of-mass energies between 14 GeV and 44 GeV were used to study moments of event shape distributions. The data were compared with Monte Carlo models and with predictions from QCD NLO order calculations. The strong coupling constant measured from the moments is alpha_S(M_Z) = 0.1286 +/- 0.0007 (stat) +/- 0.0011 (expt) +/- 0.0022 (had) +/- 0.0068 (theo), alpha_S(M_Z) = 0.1286 +/- 0.0072 (total error), consistent with the world average. However, systematic deficiencies in the QCD NLO order predictions are visible for some of the higher moments.
A new evaluation of the hadronic vacuum polarization contribution to the muon magnetic moment is presented. We take into account the reanalysis of the low-energy ee annihilation cross section into hadrons by the CMD-2 Collaboration. The agreement between ee and $tau$ spectral functions in the $pipi$ channel is found to be much improved. Nevertheless, significant discrepancies remain in the center-of-mass energy range between 0.85 and $1.0 {rm GeV}/c^2$.The deviations from the measurement at BNL are found to be $(22.1 pm 7.2 pm 3.5 pm 8.0)~10^{-10}$ (1.9 $sigma$) and $(7.4 pm 5.8 pm 3.5 pm 8.0)~10^{-10}$ (0.7 $sigma$) for the ee- and $tau$-based estimates, respectively, where the second error is from the nonhadronic contributions and the third one from the BNL measurement. Taking into account the $rho^- - rho^0$ mass splitting determined from the measured spectral functions increases the $tau$-based estimate and leads to a worse discrepancy between the two estimates.
We correct an important misprint in the journal version of our earlier work on New Jet Cluster Algorithms: Next-to-leading Order QCD..., published in Nucl. Phys. B 370 (1992) 310, which may have lead to an incorrect parametrisation of the leading order QCD coefficients for the JADE type jet cluster algorithms.
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