The bb forward-backward asymmetry has been determined from the average charge how measured in a sample of 3,500,000 hadronic Z decays collected with the DELPHI detector in 1992 - 1995. The measurement is performed in an enriched b (b) over bar sample selected using an impact parameter tag and results in the following values for the bl; forward-backward asymmetry: A(FB)(b (b) over bar) (89.55 GeV) = 0.068 +/- 0.016 (stat.) +/- 0.0013(syst.) A(FB)(b (b) over bar)(91.26 GeV) = 0.0982 +/- 0.0047(stat.) +/- 0.0016(syst.) A(FB)(b (b) over bar)(92.94 GeV) = 0.123 +/- 0.016 (stat.) +/- 0.0027(syst.) The b (b) over bar charge separation required for this analysis is directly measured in the b tagged sample, while the other charge separations are obtained from a fragmentation model precisely calibrated to data. The effective weak mixing angle is deduced from the measurement to be: sin(2)theta(eff)1 = 0.23186 +/- 0.00063.
Measurement of A(FB)(b(b)over-bar) in hadronic Z decays using a jet charge technique
GASPARINI, UGO;MARGONI, MARTINO;RONCHESE, PAOLO;SIMONETTO, FRANCO;ZUMERLE, GIANNI
1999
Abstract
The bb forward-backward asymmetry has been determined from the average charge how measured in a sample of 3,500,000 hadronic Z decays collected with the DELPHI detector in 1992 - 1995. The measurement is performed in an enriched b (b) over bar sample selected using an impact parameter tag and results in the following values for the bl; forward-backward asymmetry: A(FB)(b (b) over bar) (89.55 GeV) = 0.068 +/- 0.016 (stat.) +/- 0.0013(syst.) A(FB)(b (b) over bar)(91.26 GeV) = 0.0982 +/- 0.0047(stat.) +/- 0.0016(syst.) A(FB)(b (b) over bar)(92.94 GeV) = 0.123 +/- 0.016 (stat.) +/- 0.0027(syst.) The b (b) over bar charge separation required for this analysis is directly measured in the b tagged sample, while the other charge separations are obtained from a fragmentation model precisely calibrated to data. The effective weak mixing angle is deduced from the measurement to be: sin(2)theta(eff)1 = 0.23186 +/- 0.00063.Pubblicazioni consigliate
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