We present the first measurement of the left-right asymmetry in Bhabha scattering with a polarized electron beam. The effective electron vector and axial vector couplings to the Z0 are extracted from a combined analysis of the polarized Bhabha scattering data and the left-right asymmetry previously published by this collaboration.
No description provided.
We present a precise measurement of the left-right cross section asymmetry ($A_{LR}$) for $Z$ boson production by $\ee$ collisions. The measurement was performed at a center-of-mass energy of 91.26 GeV with the SLD detector at the SLAC Linear Collider (SLC). The luminosity-weighted average polarization of the SLC electron beam was (63.0$\pm$1.1)%. Using a sample of 49,392 $\z0$ decays, we measure $A_{LR}$ to be 0.1628$\pm$0.0071(stat.)$\pm$0.0028(syst.) which determines the effective weak mixing angle to be $\swein=0.2292\pm0.0009({\rm stat.})\pm0.0004({\rm syst.})$.}
The observed, corrected, asymmetry. L and R refer to the left and right handed beam polarizations.
The left-right asymmetry and effective weak mixing angle corrected to the pole energy value, taking into account photon exchange and electro weak interferences. L and R refer to left and right beam polarizations.
We present the first measurement of the left-right cross section asymmetry (ALR) for Z boson production by e+e− collisions. The measurement was performed at a center-of-mass energy of 91.55 GeV with the SLD detector at the SLAC Linear Collider which utilized a longitudinally polarized electron beam. The average beam polarization was (22.4±0.6)%. Using a sample of 10 224 Z decays, we measure ALR to be 0.100±0.044(stat)±0.004(syst), which determines the effective weak mixing angle to be sin2θWeff=0.2378 ±0.0056(stat)±0.0005(syst).
R and L refer to Right and Left handed beam polarization.
We present a new measurement of the left-right cross section asymmetry (ALR) for Z boson production by e+e- collisions. The measurement was performed at a center-of-mass energy of 91.28 GeV with the SLD detector at the SLAC Linear Collider (SLC). The luminosity-weighted average polarization of the SLC electron beam was (77.23+-0.52)%. Using a sample of 93,644 Z decays, we measure the pole-value of the asymmetry, ALR0, to be 0.1512+-0.0042(stat.)+-0.0011(syst.) which is equivalent to an effective weak mixing angle of sin**2(theta_eff)=0.23100+-0.00054(stat.)+-0.00014(syst.).
No description provided.
The left-right asymmetry and effective weak mixing angle corrected to the pole energy value, taking into account photon exclusive and electroweak interference effects of total-state radiation.
From 1.4 million hadronic Z decays collected by the ALEPH detector at LEP, an enriched sample of Z → cc̄ events is extracted by requiring the presence of a high momentum D ∗± . The charm quark forward-backward charge asymmetry at the Z pole is measured to be A FB 0. c = (8.0 ± 2.4) % corresponding to an effective electroweak mixing angle of sin 2 θ W eff = 0.2302 ± 0.0054.
Value of SIN2TW(eff) from CQ-quark asymmetries.
No description provided.
The B<sup loc="post">0</sup> - B̄<sup loc="post">0</sup> average mixing parameter <math altimg="si1.gif"><rm><ovl type="bar" style="s">χ</ovl></rm></math> and b forward-backward asymmetry AFB<sup loc="post">0</sup>(b) are measured from a sample of about 4 200 000 Z → qq̄ events recorded with the ALEPH detector at LEP in the years 1990–1995. High transverse momentum electrons and muons produced in b semileptonic decays provide the tag of the quark flavour and of its charge. The average mixing parameter and the pole b asymmetry are measured to be <math altimg="si1.gif"><rm><ovl type="bar" style="s">χ</ovl></rm></math> = 0.1246 ± 0.0051stat ± 0.0052syst, AFB<sup loc="post">0</sup>(b) = 0.1008 ± 0.0043stat ± 0.0028syst. The value of sin<sup loc="post">2</sup>θw<sup loc="post">eff</sup> = 0.23198 ± 0.00092 is extracted from the asymmetry measurement.
ASYM(N=FB,C=OBSERVED) is observed asymmetry including BQ, CQ and backround.
No description provided.
We present final measurements of the Z boson-lepton coupling asymmetry parameters Ae, Amu, and Atau with the complete sample of polarized Z bosons collected by the SLD detector at the SLAC Linear Collider. From the left-right production and decay polar angle asymmetries in leptonic Z decays we measure Ae = 0.1544 +- 0.0060, Amu = 0.142 +- 0.015, and Atau = 0.136 +- 0.015. Combined with our left-right asymmetry measured from hadronic decays, we find Ae = 0.1516 +- 0.0021. Assuming lepton universality, we obtain a combined effective weak mixing angle of sin**2 theta^{eff}_W = 0.23098 +- 0.00026.
No description provided.
We present a measurement of the forward-backward charge asymmetry in hadronic decays of the Z 0 using data collected with the OPAL detector at LEP. The forward-backward charge asymmetry was measured using a weight function method which gave the number of forward events on a statistical basis. In a data sample of 448 942 hadronic Z 0 decays, we have observed a charge asymmetry of A h = 0.040±0.004 (stat.)±0.006 (syst.)±0.002 (B 0 B 0 mix.), taking into account the effect of B 0 B 0 mixing. In the framework of the standard model, this asymmetry corresponds to an effective weak mixing angle averaged over five quark flavours of sin 2 θ W = 0.2321 ± 0.0017 ( stat. ) ± 0.0027 ( syst. ) ± 0.0009 (B 0 B 0 mix.). The result agrees with the value obtained from the Z 0 line shape and lepton pair forward-backward asymmetry.
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The second systematic error is due to the uncertainty in the correction for B.BBAR mixing which had been applied to the data.
We have measured the forward-backward asymmetry in Z 0 → b b decays using hadronic events containing muons and electrons. The data sample corresponds to 118 200 hadronic events at √ s ≈ M z . From a fit to the single and dilepton p and P ⊥ spectra, we determine A b b =0.130 −0.042 +0.044 including the correction for B 0 − B 0 mixing.
Observed asymmetry from fit to single and dilepton P and PT spectra assuming no mixing.
Asymmetry corrected for the effects of mixing using the L3 observed mixing parameter chi(B) = 0.178 +0.049,-0.040.
We have measured the forward-backward asymmetry in e + e − → b b and e + e − → c c processes using hadronic events containing muons or electrons. The data sample corresponds to 4100000 hadronic decays of the Z 0 . From a fit to the single lepton and dilepton p and p T spectra, we determine A b b =0.086±0.015±0.007 and A c c =0.083±0.038±0.027 at the effective center-of-mass energy √ s =91.24 GeV. These measurements yield a value of the electroweak mixing angle sin 2 θ w =0.2336±0.0029 .
No description provided.
No description provided.
No description provided.