Determination of event shape distributions and αs b from {Mathematical expression} events at LEP

Abstract

In hadronic Z0 decays collected by the OPAL experiment at LEP, event shape variables such as jet rates, jet masses, thrust and the energy-energy correlation for {Mathematical expression} events are compared to those for all flavours using secondary vertex information to tag the b quarks. The measured distributions are found to be well described by an O"(αs) calculation for heavy quarks as well as by parton shower simulations. We also determine the ratio of the strong coupling constant for b quarks and all quarks, αs b/αs incl, from these distributions. We find {Mathematical expression} where the errors are the statistical and systematic errors. The result can be converted into the ratio for ..