A Study of Jet Rates and Measurement of [alpha][sub S] at the Z[sup 0] Resonance
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Published: 1993
Total Pages: 156
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DOWNLOAD EBOOKThis experiment was performed with the SLD detector at the Stanford Linear Accelerator Center. Only charged tracks measured in the central drift chamber were used for the measurement of the jet production rates. The value of the strong coupling [alpha][sub s](M[sub Z][sup o]) is determined from the production rates of jets in hadronic Z[sup 0] decays in e[sup +] e[sup [minus]] annihilations. The relative jet rates are obtained using the JADE-type algorithms. The results are compared with the jet rates obtained from a new jet algorithm proposed by N. Brown et al. called the Durham'' algorithm. The data can be well described by O([alpha][sub s][sup 2]) QCD calculations and by QCD shower model calculations. A fit of the theoretical predictions to the data taken with the SLD yields a value, [alpha][sub s](M[sub Z][sup o]) = 0.120 [plus minus] 0.002(stat.) [plus minus] 0.003(exp.)[sub [minus]0.009][sup +0.011](theor.). The error is dominated by the theoretical uncertainties. The measurement is compared with results from other experiments and it is shown that the value obtained for [alpha][sub s] agrees well with these results and furthermore supports the evidence for the running of the strong coupling, consistent with the non-Abelian nature of QCD. The Stanford Linear Collider (SLC) can deliver partially longitudinally polarized electrons to the interaction point. Jet production rates and values for [alpha][sub s] are calculated both for right-handed and left-handed initial state electrons. All results are consistent with the unpolarized result, as predicted by the Standard Model.