Liu, Bo
E+ E- --> QUARK QUARKBAR
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Measurement of the cross section of W-boson pair production at LEP.

The L3 collaboration Achard, P. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett.B 600 (2004) 22-40, 2004.
Inspire Record 658254 DOI 10.17182/hepdata.48792

The cross section of W-boson pair-production is measured with the L3 detector at LEP. In a data sample corresponding to a total luminosity of 629.4/pb, collected at centre-of-mass energies ranging from 189 to 209 GeV, 9834 four-fermion events with W bosons decaying into hadrons or leptons are selected. The total cross section is measured with a precision of 1.4 % and agrees with the Standard Model expectation. Assuming charged-lepton universality, the branching fraction for hadronic W-boson decays is measured to be: Br(W-->hadrons) = 67.50 +- 0.42 (stat.) +- 0.30(syst.) %, in agreement with the Standard Model. Differential cross sections as a function of the W- production angle are also measured for the semi-leptonic channels qqev and qqmv.

11 data tables
Table 1

Measured cross section for the process E+ E- --> LEPTON NU LEPTON NU.

Table 2

Measured cross section for the process E+ E- --> QUARK QUARKBAR ELECTRON NEUTRINO.

Table 3

Measured cross section for the process E+ E- --> QUARK QUARKBAR MUON NEUTRINO.

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Forward - backward charge asymmetry of quark pairs produced at the KEK TRISTAN e+ e- collider

The AMY collaboration Stuart, D. ; Breedon, R.E. ; Chinitz, L.M. ; et al.
Phys.Rev.D 49 (1994) 3098-3105, 1994.
Inspire Record 378569 DOI 10.17182/hepdata.22552

We report on a measurement of the forward-backward charge asymmetry in e+e−→qq¯ at KEK TRISTAN, where the asymmetry is near maximum. We sum over all flavors and measure the asymmetry by determining the charge of the quark jets. In addition we exploit flavor dependencies in the jet charge determination to enhance the contributions of certain flavors. This provides a check on the asymmetries of individual flavors. The measurement agrees with the standard model expectations.

1 data table
Table 1

Forward--backward asymmetry summed over all flavours of quarks.


A Measurement of the Z0 ---> b anti-b forward - backward asymmetry

The L3 collaboration Adeva, B. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett.B 252 (1990) 713-721, 1990.
Inspire Record 301901 DOI 10.17182/hepdata.29506

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.

3 data tables
Table 1

Observed asymmetry from fit to single and dilepton P and PT spectra assuming no mixing.

Table 2

Asymmetry corrected for the effects of mixing using the L3 observed mixing parameter chi(B) = 0.178 +0.049,-0.040.

Table 3

SIN2TW determined from the asymmetry measurement.


Measurement of $\Z^0 \to b \bar{b}$ Decay Properties

The L3 collaboration Adeva, B. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett.B 241 (1990) 416-424, 1990.
Inspire Record 295040 DOI 10.17182/hepdata.29716

We have measured the properties of Z 0 → b b decays using a sample of 944 inclusive muon events, corresponding to 18 000 hadron events obtained with the L3 detector at LEP. We measured the partial decay width of the Z 0 into b b , Γ b b =353±48 MeV , and we determined the vector coupling of the Z 0 to the b quark; g rmv 2 (b)=0.095±0.047. We measured the forward-backward charge asymmetry in e + e − → b b events at √ s ≈ M v , and obtained A b b =13.3±9.9% .

1 data table
Table 1

BOTTOM quark charge asymmetry measurement.


FORWARD - BACKWARD CHARGE ASYMMETRY IN e+ e- ---> HADRON JETS

The AMY collaboration Stuart, D. ; Breedon, R.E. ; Kim, G.N. ; et al.
Phys.Rev.Lett. 64 (1990) 983, 1990.
Inspire Record 283082 DOI 10.17182/hepdata.19965

The forward-backward asymmetry of quarks produced in e+e− annihilations, summed over all flavors, is measured at √s between 50 and 60.8 GeV. Methods of determining the charge direction of jet pairs are discussed. The asymmetry is found to agree with the five-flavor standard model.

1 data table
Table 1

Forward backward asymmetry summed over all flavours of quarks.