Measurements of the bb~ production cross section and forward backward asymmetry at centre-of-mass energies above the Z pole at LEP

TL;DR

This paper reports measurements of the b quark production cross section and forward-backward asymmetry at energies above the Z pole at LEP, providing insights into electroweak interactions and testing the Standard Model.

Contribution

It presents new measurements of Rb and A^b_fb at energies above the Z pole using advanced b-tagging and lepton-tagging methods, enhancing precision in electroweak tests.

Findings

Rb at 189 GeV: 0.163 +/- 0.013 (stat.) +/- 0.005 (syst.)

A^b_fb at 189 GeV: 0.61 +/- 0.18 (stat.) +/- 0.09 (syst.)

Results are consistent with Standard Model predictions.

Abstract

The measurements of Rb = sigma(e+e- -> bb~)/sigma(e+e- -> qq~) and of the b quark forward-backward charge asymmetry, A^b_fb, at centre-of-mass energies above the Z pole are described. The measurement of Rb is performed at \root{s} between 130 and 189 GeV using a b-tagging method that exploits the relatively large decay length of b-hadrons. The measurement of A^b_fb is performed using the large statistics event sample collected at \root{s}=189 GeV with a lepton-tag analysis based on the selection of prompt muons and electrons. The results at \root{s}=189 GeV are: Rb = 0.163 +/- 0.013 (stat.) +/- 0.005 (syst.), A^b_fb = 0.61 +/- 0.18 (stat.) +/- 0.09 (syst.).