A measurement of Rb using mutually exclusive tags

Manoj THULASIDAS, Singapore Management University

Abstract

A measurement of Rb using ve mutually exclusive hemisphere tags has been performed by ALEPH using the full LEP1 statistics. Three tags are designed to select the decay of the Z0 to b quarks, while the remaining two select Z0 decays to c and light quarks, and are used to measure the tagging eciencies. The result, Rb = 0:2159 0:0009(stat) 0:0011(syst), is in agreement with the electroweak theory prediction of 0:21580:0003.