Measurement of Rb in e+e- Collisions at 182 - 209 GeV

TL;DR

This paper reports measurements of the ratio Rb, representing the production rate of b quarks relative to all quarks in electron-positron collisions at energies between 182 and 209 GeV, confirming consistency with the Standard Model.

Contribution

First precise measurements of Rb at these energies using multiple tagging techniques, providing data that supports the Standard Model predictions.

Findings

Measured Rb ratio is 1.055±0.031±0.037

Results are compatible with Standard Model expectations

Data collected at multiple energies between 182 and 209 GeV

Abstract

Measurements of Rb, the ratio of the bbbar cross-section to the qqbar cross- section in e+e- collisions, are presented. The data were collected by the OPAL experiment at LEP at centre-of-mass energies between 182 GeV and 209 GeV. Lepton, lifetime and event shape information is used to tag events containing b quarks with high efficiency. The data are compatible with the Standard Model expectation. The mean ratio of the eight measurements reported here to the Standard Model prediction is 1.055+-0.031+-0.037, where the first error is statistical and the second systematic.