A measurement of the weak axial couplings of the b- and c-quark

Abstract

The forward-backward charge asymmetries of the b and c quarks are measured with the JADE detector at the e + e − storage ring PETRA at √ s = 35 GeV and 44 GeV using both electrons and muons to tag the heavy quarks. At √ s = 35 GeV, a simultaneous fit for the two asymmetries yields the result A b = −9.3 ± 5.2% (stat.) and A c = −9.6±4.0% (stat.). Combining the results of 1 parameter fits of the asymmetries at both energies gives a b = −0.72±0.34 and a c = 0.79 ± 0.40 respectively. The mixing parameter for continuum b b ̄ - production is determined to be χ = 0.24 ± 0.12 if both heavy quark coupling constants are constrained to their Standard Model values.