Search for a Z-prime at the Z resonance

The L3 collaboration Adriani, O. ; Aguilar-Benitez, M. ; Ahlen, S.P. ; et al.
Phys.Lett.B 306 (1993) 187-196, 1993.
Inspire Record 355489 DOI 10.17182/hepdata.28919

The search for an additional heavy gauge boson Z′ is described. The models considered are based on either a superstring-motivated E 6 or on a left-right symmetry and assume a minimal Higgs sector. Cross sections and asymmetries measured with the L3 detector in the vicinity of the Z resonance during the 1990 and 1991 running periods are used to determine limits on the Z-Z′ gauge boson mixing angle and on the Z′ mass. For Z′ masses above the direct limits, we obtain the following allowed ranges of the mixing angle, θ M at the 95% confidence level: −0.004 ⪕ θ M ⪕ 0.015 for the χ model, −0.003 ⪕ θ M ⪕ 0.020 for the ψ model, −0.029 ⪕ θ M ⪕ 0.010 for the η model, −0.002 ⪕ θ M ⪕ 0.020 for the LR model,

2 data tables match query

Data taken during 1990.

Data taken during 1991.


Measurement of hadron and lepton pair production from e+ e- annihilation at center-of-mass energies of 130-GeV and 136-GeV

The ALEPH collaboration Buskulic, D. ; De Bonis, I. ; Decamp, D. ; et al.
Phys.Lett.B 378 (1996) 373-384, 1996.
Inspire Record 421552 DOI 10.17182/hepdata.47801

Hadronic and leptonic cross-sections and forward-backward asymmetries are measured using 5.7 pb −1 of data taken with the ALEPH detector at LEP at centre-of-mass energies of 130 and 136 GeV. The results agree with Standard Model expectations. The measurement of hadronic cross-sections far away from the Z resonance improves the determination of the interference between photon and Z exchange. Constraints on models with extra Z bosons are presented.

5 data tables match query

Forward-Backward Asymmetry with loose SPRIME cuts.

Forward-Backward Asymmetry with tight SPRIME cuts.

Forward-Backward Asymmetry with loose SPRIME cuts.

More…

Measurement of hadron and lepton pair production at 130-GeV less than S**(1/2) less than 189-GeV at LEP

The L3 collaboration Acciarri, M. ; Achard, P. ; Adriani, O. ; et al.
Phys.Lett.B 479 (2000) 101-117, 2000.
Inspire Record 513676 DOI 10.17182/hepdata.48958

We report on measurements of e+e- annihilation into hadrons and lepton pairs. The data have been collected with the L3 detector at LEP at centre-of-mass energies between 130 and 189 GeV. Using a total integrated luminosity of 243.7 pb^-1, 25864 hadronic and 8573 lepton-pair events are selected for the measurement of cross sections and leptonic forward-backward asymmetries. The results are in good agreement with Standard Model predictions.

3 data tables match query

Forward backward asymmetry for lepton-pair events.

Measured cross sections for the tau-pair events.

Measured cross sections for the electron-pair events. For Bhabha scattering events both the leptons have to be inside 44 to 136 degrees.


Measurement of electroweak parameters from hadronic and leptonic decays of the Z0

The L3 collaboration Adeva, B. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Z.Phys.C 51 (1991) 179-204, 1991.
Inspire Record 314418 DOI 10.17182/hepdata.14940

From the measured ratio of the invisible and the leptonic decay widths of theZ0, we determine the number of light neutrino species to beNv=3.05±0.10. We include our measurements of the forward-backward asymmetry for the leptonic channels in a fit to determine the vector and axial-vector neutral current coupling constants of charged leptons to theZ0. We obtain\(\bar g_V=- 0.046_{ - 0.012}^{ + 0.015}\) and\(\bar g_A=- 0.500 \pm 0.003\). In the framework of the Standard Model, we estimate the top quark mass to bemt=193−69+52±16 (Higgs) GeV, and we derive a value for the weak mixing angle of sin2θW=1−(MW/MZ)2=0.222 ± 0.008, corresponding to an effective weak mixing angle of\(\sin ^2 \bar \theta _W= 0.2315\pm0.0025\).

6 data tables match query

Asymmetry determined from the number of events in the forward and backward hemisphere. Estimated systematic error is 0.005.

Asymmetry determined using the maximum likelihood method. Estimated systematic error is 0.005.

Asymmetry determined from the number of events in the forward and backward hemisphere. Estimated systematic error is <0.01.

More…

Measurement of cross-sections and leptonic forward - backward asymmetries at the z pole and determination of electroweak parameters

The L3 collaboration Acciarri, M. ; Adam, A. ; Adriani, O. ; et al.
Z.Phys.C 62 (1994) 551-576, 1994.
Inspire Record 374696 DOI 10.17182/hepdata.48198

We report on the measurement of the leptonic and hadronic cross sections and leptonic forward-backward asymmetries at theZ peak with the L3 detector at LEP. The total luminosity of 40.8 pb−1 collected

12 data tables match query

Results from 1990 data. Additional systematic uncertainty of 0.005.. Acollinearity required to be <15 degrees.

Results from 1991 data. Additional systematic uncertainty of 0.002.. Acollinearity required to be <15 degrees.

Results from 1992 data. Additional systematic uncertainty of 0.002.. Acollinearity required to be <15 degrees.

More…