Measurement of $R_b$ = $\Gamma_{b\overline{b}}$/$\Gamma_{had}$ using leptons, event shape and multivariable tags at LEP

The partial decay width of the Z to bb quark pairs has been precisely measured by the LEP collaborations using methods based on lifetime tags. In this paper, alternative measurements using lepton, event shape and multivariate tags are presented and the combined results are compared with the lifetime tagging measurements. The accuracy of lifetime measurements is actually dominated by systematics. Any improvement in precision requires better external knowledge of the charm and light quark physics a ecting Rb . However, analyses combining leptons, event shape and lifetime information have not the same limitations in systematic errors and the statistics of analyzed events is still partial. Therefore including the high global LEP statistics, such alternative analyses are promising and interesting improvements in precision on Rb can be re