Measurement of observables sensitive to coherence effects in hadronic Z decays with the OPAL detector at LEP

Understand

A study of QCD coherence is presented based on a sample of about 397000 $e^+e^-$ hadronic annihilation events collected at $\sqrt{s}=91$ GeV with the OPAL detector at LEP.

• The study is based on four recently proposed observables that are sensitive to coherence effects in the perturbative regime.
• The measurement of these observables is presented, along with a comparison with the predictions of different parton shower models.
• The models include both conventional parton shower models and dipole antenna models.