Abstract
The cross section and jet rates ofZ 0 decays into photons and quarks are compared with matrix element Monte Carlos ofO(ααs). Good agreement is found between data and theoretical predictions. From the ratio of events with three jets plus a photon to those with two jets plus a photon, αs in first order is determined to be 0.176±0.010. Combining the cross section of final state photon events with the LEP average hadronic partial decay width of theZ 0, the widths of theZ 0 into up and down type quarks can be calculated. The results
are in good agreement with the standard model expectation. A comparison of the measured cross section as a function ofy cut with predictions of QCD shower models shows that, at the current level of accuracy ARIADNE and, to a lesser extent, HERWIG and JETSET can reproduce the measurement.
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OPAL Collaboration., Acton, P.D., Alexander, G. et al. Studies of strong and electroweak interactions using final state photon emission in hadronicZ 0 decays. Z. Phys. C - Particles and Fields 58, 405–418 (1993). https://doi.org/10.1007/BF01557697
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DOI: https://doi.org/10.1007/BF01557697