First measurement of the left-right cross-section asymmetry in Z boson production by e+ e- collisions

The SLD collaboration Abe, K. ; Abt, I. ; Acton, P.D. ; et al.
Phys.Rev.Lett. 70 (1993) 2515-2520, 1993.
Inspire Record 352667 DOI 10.17182/hepdata.19765

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).

2 data tables

R and L refer to Right and Left handed beam polarization.

Effective weak mixing angle.


A Measurement of alpha-s from jet rates at the Z0 resonance

The SLD collaboration Abe, K. ; Abt, I. ; Acton, P.D. ; et al.
Phys.Rev.Lett. 71 (1993) 2528-2532, 1993.
Inspire Record 356912 DOI 10.17182/hepdata.19724

We have determined the strong coupling αs from measurements of jet rates in hadronic decays of Z0 bosons collected by the SLD experiment at SLAC. Using six collinear and infrared safe jet algorithms we compared our data with the predictions of QCD calculated up to second order in perturbation theory, and also with resummed calculations. We find αs(MZ2)=0.118±0.002(stat)±0.003(syst)±0.010(theory), where the dominant uncertainty is from uncalculated higher order contributions.

1 data table

The second systematic error comes from the theoretical uncertainties.


Measurement of alpha-s from energy-energy correlations at the Z0 resonance

The SLD collaboration Abe, K. ; Abt, I. ; Ash, W.W. ; et al.
Phys.Rev.D 50 (1994) 5580-5590, 1994.
Inspire Record 373005 DOI 10.17182/hepdata.17744

We have determined the strong coupling $\as$ from a comprehensive study of energy-energy correlations ($EEC$) and their asymmetry ($AEEC$) in hadronic decays of $Z~0$ bosons collected by the SLD experiment at SLAC. The data were compared with all four available predictions of QCD calculated up to $\Oa2$ in perturbation theory, and also with a resummed calculation matched to all four of these calculations. We find large discrepancies between $\as$ values extracted from the different $\Oa2$ calculations. We also find a large renormalization scale ambiguity in $\as$ determined from the $EEC$ using the $\Oa2$ calculations; this ambiguity is reduced in the case of the $AEEC$, and is very small when the matched calculations are used. Averaging over all calculations, and over the $EEC$ and $AEEC$ results, we obtain $\asz=0.124~{+0.003}_{-0.004} (exp.) \pm 0.009 (theory).$

5 data tables

Statistical errors only.

Statistical errors only.

ALPHAS from the EEC O(ALPHAS**2) measurement.

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Precise Measurement of the Left-Right Cross Section Asymmetry in $Z$ Boson Production by $\ee$ Collisions

The SLD collaboration Abe, K. ; Abt, I. ; Ash, W.W. ; et al.
Phys.Rev.Lett. 73 (1994) 25-29, 1994.
Inspire Record 373007 DOI 10.17182/hepdata.19681

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 $\swein=0.2292\pm0.0009({\rm stat.})\pm0.0004({\rm syst.})$.}

2 data tables

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.


A Search for jet handedness in hadronic Z0 decays

The SLD collaboration Abe, K. ; Abt, I. ; Ahn, C.J. ; et al.
Phys.Rev.Lett. 74 (1995) 1512-1516, 1995.
Inspire Record 378343 DOI 10.17182/hepdata.19666

We have searched for signatures of polarization in hadronic jets from $Z~0 \rightarrow q \bar{q}$ decays using the ``jet handedness'' method. The polar angle asymmetry induced by the high SLC electron-beam polarization was used to separate quark jets from antiquark jets, expected to be left- and right-polarized, respectively. We find no evidence for jet handedness in our global sample or in a sample of light quark jets and we set upper limits at the 95\% C.L. of 0.063 and 0.099 respectively on the magnitude of the analyzing power of the method proposed by Efremov {\it et al.}

1 data table

Polarized E- beam. Events were classified as being of light or heavy flavors based on impact parameters of charged tracks measured in the vertex detector. Jet handedness are measured for helicity-based and chirality-based analysis (seetext). C=95PCT CL indicates the upper limits at the 95 PCT C.L. on the magnitudes.


Measurement of alpha-s (M(Z)**2) from hadronic event observables at the Z0 resonance

The SLD collaboration Abe, K. ; Abt, I. ; Ahn, C.J. ; et al.
Phys.Rev.D 51 (1995) 962-984, 1995.
Inspire Record 378545 DOI 10.17182/hepdata.22450

The strong coupling alpha_s(M_Z^2) has been measured using hadronic decays of Z^0 bosons collected by the SLD experiment at SLAC. The data were compared with QCD predictions both at fixed order, O(alpha_s^2), and including resummed analytic formulae based on the next-to-leading logarithm approximation. In this comprehensive analysis we studied event shapes, jet rates, particle correlations, and angular energy flow, and checked the consistency between alpha_s(M_Z^2) values extracted from these different measures. Combining all results we obtain alpha_s(M_Z^2) = 0.1200 \pm 0.0025(exp.) \pm 0.0078(theor.), where the dominant uncertainty is from uncalculated higher order contributions.

16 data tables

Final average value of alpha_s. The second (DSYS) error is from the uncertainty on the theoretical part of the calculation.

TAU is 1-THRUST.

RHO is the normalized heavy jet mass MH**2/EVIS**2.

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Polarized Bhabha Scattering and a Precision Measurement of the Electron Neutral Current Couplings

The SLD collaboration Abe, K. ; Abt, I. ; Ahn, C.J. ; et al.
Phys.Rev.Lett. 74 (1995) 2880-2884, 1995.
Inspire Record 376916 DOI 10.17182/hepdata.19647

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.

1 data table

No description provided.


A Test of the flavor independence of strong interactions

The SLD collaboration Abe, K. ; Abt, I. ; Ahn, C.J. ; et al.
Phys.Rev.D 53 (1996) 2271-2275, 1996.
Inspire Record 382002 DOI 10.17182/hepdata.22341

We present a comparison of the strong couplings of light ($u$, $d$, and $s$), $c$, and $b$ quarks determined from multijet rates in flavor-tagged samples of hadronic $Z~0$ decays recorded with the SLC Large Detector at the SLAC Linear Collider. Flavor separation on the basis of lifetime and decay multiplicity differences among hadrons containing light, $c$, and $b$ quarks was made using the SLD precision tracking system. We find: $\alpha_s{_{\vphantom{y}}}~{uds}/{\alpha_s{_{\vphantom{y}}}~{\rm all}} = 0.987 \pm 0.027({\rm stat}) \pm 0.022({\rm syst}) \pm 0.022({\rm theory})$, $\alpha_s{_{\vphantom{y}}}~c/{\alpha_s{_{\vphantom{y}}}~{\rm all}} = 1.012 \pm 0.104 \pm 0.102 \pm 0.096$, and $\alpha_s{_{\vphantom{y}}}~b/{\alpha_s{_{\vphantom{y}}}~{\rm all}} = 1.026 \pm 0.041 \pm 0.041\pm 0.030.$

1 data table

No description provided.


Precise measurement of the left-right cross-section asymmetry in Z boson production by e+ e- collisions

The SLD collaboration Schumm, B.A. ;
Nucl.Phys.B Proc.Suppl. 40 (1995) 497-503, 1995.
Inspire Record 389176 DOI 10.17182/hepdata.31853

We present a precise measurement of the left-right cross section asymmetry ( A LR ) for Z boson production by e + e − 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±1.1)%. Using a sample of 49,392 Z decays, we measure A LR to be 0.1628±0.0071(stat.)±0.0028(syst.) which determines the effective weak mixing angle to be sin 2 θ W f eff = 0.2292 ± 0.0009(stat.) ± 0.0004(syst.).

1 data table

R and L refer to Right and Left handed electron beam polarization. ASYM is defined as follows : ASYM = ((SIG(C=L)-SIG(C=R))/(SIG(C=L)+SIG(C=R)).


Comparison of a new calculation of energy-energy correlations with e+ e- ---> hadrons data at the Z0 resonance

The SLD collaboration Abe, K. ; Abt, I. ; Ahn, C.J. ; et al.
Phys.Rev.D 52 (1995) 4240-4244, 1995.
Inspire Record 39718 DOI 10.17182/hepdata.22336

We have compared a new QCD calculation by Clay and Ellis of energy-energy correlations (EEC’s) and their asymmetry (AEEC’s) in e+e− annihilation into hadrons with data collected by the SLD experiment at SLAC. From fits of the new calculation, complete at O(αs2), we obtained αs(MZ2)=0.1184±0.0031(expt)±0.0129(theory) (EEC) and αs(MZ2)=0.1120±0.0034(expt)±0.0036(theory) (AEEC). The EEC result is significantly lower than that obtained from comparable fits using the O(αs2) calculation of Kunszt and Nason.

1 data table

The data are compared to the predictions of Monte-Carlo. Two values of ALPHA_S are corresponded the two theoretical models used in the comparison.