Measurements of R_b, A_FB^b and A_FB^c in e+e- Collisions at 130-189 GeV

TL;DR

This paper reports measurements of the bottom and charm quark forward-backward asymmetries and the ratio of bottom to total hadronic cross sections in electron-positron collisions at energies between 130 and 189 GeV, using data from the OPAL detector, with results consistent with the Standard Model.

Contribution

It provides new measurements of Rb, A_FB^b, and A_FB^c at high energies, employing multiple tagging techniques, and confirms Standard Model predictions in this energy range.

Findings

Measured Rb, A_FB^b, and A_FB^c at 130-189 GeV.

Results agree with Standard Model predictions.

Used secondary vertex tags and lepton-based methods.

Abstract

The cross-section ratio Rb=sigma(e+e- to b-antib)/sigma(e+e- to q-antiq) and the bottom and charm forward-backward asymmetries AFB^b and AFB^c are measured using event samples collected by the OPAL detector at centre-of-mass energies between 130 and 189 GeV. Events with bottom quark production are selected with a secondary vertex tag, and a hemisphere charge algorithm is used to extract AFB^b. In addition, the bottom and charm asymmetries are measured using leptons from semileptonic decays of heavy hadrons and pions from D*+ to D0pi+ decays. The results are in agreement with the Standard Model predictions.