Measurement of the Reactions $e^+ e^- \to \mu^+ \mu^-$ and $e^+ e^- \to \tau^+ \tau^-$ Between $\sqrt{s}=50$-{GeV} and 60.8-{GeV}

The VENUS collaboration Abe, K. ; Amako, K. ; Arai, Y. ; et al.
Z.Phys.C 48 (1990) 13-22, 1990.
Inspire Record 294672 DOI 10.17182/hepdata.38414

The angular distributions of the reactione+e−→μ+μ− ande+e+→τ+τ− have been measured between\(\sqrt s= 50\) and 60.8 GeV with the VENUS detector at TRISTAN. The average total cross section and the forward-backward charge asymmetry for μ-pair production are observed to be 28.3±1.4±0.8 pb and (−29.0−4.8+5.0±0.5)%, and those for τ-pair production are 27.6±1.7±1.0 pb and (−32.8−6.2+6.4±1.5)% at\(\langle \sqrt s \rangle \). These values are consistent with the predictions of the standard model of electroweak interactions.

5 data tables

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Experimental limits on extra Z bosons from e+ e- annihilation data with the VENUS detector at s**(1/2) = 50-GeV to approximately 64-GeV

The VENUS collaboration Abe, K. ; Amako, K. ; Arai, Y. ; et al.
Phys.Lett.B 246 (1990) 297-305, 1990.
Inspire Record 296392 DOI 10.17182/hepdata.29664

We have tested extra Z models in the reactions e + e − → μ + μ − , τ + τ − and hadrons in the energy range 50< s <64 GeV using the VENUS detector at the TRISTAN e + e − storage ring. Our data are in good agreement with the standard model prediction ( χ 2 N Df = 2.9 31 ) ). We have obtained 90% confidence-level lower limits of 105, 125 and 231 GeV for the masses of Z Ψ , Z η and Z χ bosons which are expected from the E 6 grand unified theory. We also place a 90% confidence-level lower limit of 426 GeV for the mass of an extra-Z boson whose couplings to quarks and leptons are assumed to be the same as those for the standard Z boson. Our results exceed the previous experimental limits from the p p collider experiments, although there have been some combined analyses reporting the limits better than those obtained in the present analysis.

5 data tables

New measurements.

New measurements. Statistical and systematic errors combined in quadrature.

New measurements.

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Determination of the QCD scale parameter Lambda (ms) with QCD cascade on the basis of the next-to-leading logarithmic approximation

The VENUS collaboration Abe, K. ; Amako, K. ; Arai, Y. ; et al.
Phys.Lett.B 240 (1990) 232-236, 1990.
Inspire Record 296684 DOI 10.17182/hepdata.29690

The relative production ratio of 3-jet events to the total number of hadronic events was studied in e + e − annihilations at centre-of-mass energies between 54 and 61.4 GeV. The QCD scale parameter has been determined to be Λ MS =254 −47 +55 ±56 MeV on the basis of a QCD cascade with the next-to-leading logarithmic approximation.

2 data tables

Data are uncorrected for initial radiation, detector effects, and quark hadronization.

LAMBDA-MSBAR determined from the 3-jet ratio.


Measurement of the Differential Cross-sections of $e^+ e^- \to \gamma \gamma$ and $e^+ e^- \to \gamma \gamma \gamma$ at $\sqrt{s}=55$-{GeV}, 56-{GeV}, 56.5-{GeV} and 57-{GeV} and Search for Unstable Photino Pair Production

The VENUS collaboration Abe, K. ; Amako, K. ; Arai, Y. ; et al.
Z.Phys.C 45 (1989) 175, 1989.
Inspire Record 280669 DOI 10.17182/hepdata.15298

Differential cross sections fore+e−→γγ have been measured at center-of-mass energies of 55, 56, 56.5 and 57 GeV. The results are in good agreement with those predicted by QED. Possible deviations from QED are studied in terms of contact interactions, and the limits on compositeness scales are obtained. Using events with a gramma pair in the final state, a search is made for the pair production of unstable photons,\(e^ +e^ -\to \tilde \gamma\tilde \gamma \). No candidate events were found and a new limit on the photino mass is obtained.

11 data tables

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Measurement of R and Search for New Quark Flavors Decaying Into Multi - Jet Final States in $e^+ e^-$ Collisions Between 54-{GeV} and 61.4-{GeV} c.m. Energies

The VENUS collaboration Abe, K. ; Amako, K. ; Arai, Y. ; et al.
Phys.Lett.B 234 (1990) 382-388, 1990.
Inspire Record 283774 DOI 10.17182/hepdata.29755

We accumulated e + e − annihilations into multi-hadrons at CM energies between 54.0 and 61.4 GeV with the VENUS detector at TRISTAN. Measured R -ratios are consistent with the standard model using the Z-boson mass; 91.1 GeV/ c 2 . Using two new observables, we searched for a planar four-jet and other multi-jet events resulting from the decay of a charge — 1 3 e b ' quark. Having observed no positive signals, we excluded b' masses between 19.4 and 28.2 GeV/ c 2 with a 95% confidence level, regardless of branching into charged current and loop-induced flavor-changing neutral current decay, including a possible Higgs decay process. The charge + 2 3 e top quark was excluded below f30.2 GeV/ c 2 .

1 data table

R value measurements.