A significant charge asymmetry is observed in the hadronic Z decays collected with the ALEPH detector at LEP. The asymmetry expressed in terms of the difference in momentum weighted charges in the two event hemispheres is measured to be <Q forward> - <Q backward> = -0.0084 +/- 0.0015 (stat.) +/- 0.0004 (exp. sys.). In the framework of the standard model this can be interpreted as a measurement of the effective electroweak mixing angle, sin^2(teta_W((M_Z)^2)) = 0.2300 +/- 0.0034 (stat.) +/- 0.0010 (exp. sys.) +/- 0.0038 (theor. sys.) or of the ratio of the vector to axial-vector coupling constants of the electron, g _Ve/g_Ae = + 0.073 +/- 0.024.
Measurement of charge asymmetry in hadronic Z decays
G. Batignani;CIOCCI, MARIA AGNESE;FERRANTE, ISIDORO;FIDECARO, FRANCESCO;F. Forti;MESSINEO, ALBERTO MARIA;TONELLI, GUIDO EMILIO;G. Triggiani;
1991-01-01
Abstract
A significant charge asymmetry is observed in the hadronic Z decays collected with the ALEPH detector at LEP. The asymmetry expressed in terms of the difference in momentum weighted charges in the two event hemispheres is measured to be-= -0.0084 +/- 0.0015 (stat.) +/- 0.0004 (exp. sys.). In the framework of the standard model this can be interpreted as a measurement of the effective electroweak mixing angle, sin^2(teta_W((M_Z)^2)) = 0.2300 +/- 0.0034 (stat.) +/- 0.0010 (exp. sys.) +/- 0.0038 (theor. sys.) or of the ratio of the vector to axial-vector coupling constants of the electron, g _Ve/g_Ae = + 0.073 +/- 0.024.
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