HEPData Search

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rivet Analysis
Measurement of dijet angular distributions at CDF

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.

Phys.Rev.Lett. 77 (1996) 5336-5341, 1996.

Inspire Record 423414 DOI 10.17182/hepdata.54980

We have used 106 pb~-1 of data collected in proton-antiproton collisions at sqrt(s)=1.8 TeV by the Collider Detector at Fermilab to measure jet angular distributions in events with two jets in the final state. The angular distributions agree with next to leading order (NLO) predictions of Quantum Chromodynamics (QCD) in all dijet invariant mass regions. The data exclude at 95% confidence level (CL) a model of quark substructure in which only up and down quarks are composite and the contact interaction scale is Lambda_ud(+) < 1.6 TeV or Lambda_ud(-) < 1.4 TeV. For a model in which all quarks are composite the excluded regions are Lambda(+) < 1.8 TeV and Lambda(-) < 1. 6 TeV.

2 data tables

Table 1

No description provided.

Table 2

Di-jet angular ratio, defined as the number with CHI < 2.5 divided by the number with CHI between 2.5 and 5.

A Determination of alpha-s (M (Z0)) at LEP using resummed QCD calculations

The OPAL collaboration Acton, P.D. ; Alexander, G. ; Allison, John ; et al.

Z.Phys.C 59 (1993) 1-20, 1993.

Inspire Record 354188 DOI 10.17182/hepdata.14427

The strong coupling constant, αs, has been determined in hadronic decays of theZ0 resonance, using measurements of seven observables relating to global event shapes, energy correlatio

7 data tables

Table 1

Data corrected for finite acceptance and resolution of the detector and for intial state photon radiation. No corrections for hadronic effects are applied.. Errors include statistical and systematic uncertainties, added in quadrature.

Table 2

Table 3

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A Study of D*+- production in Z0 decays

The OPAL collaboration Alexander, G. ; Allison, J. ; Allport, P.P. ; et al.

Phys.Lett.B 262 (1991) 341-350, 1991.

Inspire Record 315060 DOI 10.17182/hepdata.9272

In this paper an investigation of the production of D ∗ ± mesons produced in e + e − collisions at energies around the Z 0 pole is presented. Based on 115 D ∗ ± mesons with x D∗  2E D ∗ /E cm > 0.2 the properties of D ∗ mesons produced in the reaction Z 0 → c c are studied. Fixing the yield and the fragmentation function of bottom quarks to the values obtained at LEP using lepton tags, and average energy fraction of the D ∗ ± mesons from primary charmed quarks of 〈x c → D ∗ 〉 = 0.52 ± 0.03 +- 0.01 is found and Γ z 0 →c c = (323 ± 61 ± 35) MeV is determined. The first error is the combined statistical and systematic error from this experiment, and the second the total error from other sources.

2 data tables

Table 1

FD denotes the fraction of D* mesons from primary charmed quarks, derived from the fit (see text).

Table 2

No description provided.

Measurement of the cross-sections of the reactions e+ e- ---> gamma gamma and e+ e- ---> gamma gamma gamma at LEP

The OPAL collaboration Akwawy, M.Z. ; Alexander, G. ; Allison, J. ; et al.

Phys.Lett.B 257 (1991) 531-540, 1991.

Inspire Record 302587 DOI 10.17182/hepdata.29464

The cross section of the pure QED process e + e − → γγ has been measured using data accumulated during the 1989 and 1990 scans of the Z 0 resonance at LEP. Both the energy dependence and the angular distribution are in good agreement with the QED prediction. Upper limits on the branching ratios of Z 0 → γγ , Z 0 → π 0 γ and Z 0 → ηγ have been set at 1.4×10 −4 , 1.4×10 −4 and 2.0×10 −4 respectively. Lower limits on the cutoff parameters of the modified electron propagator have been found to be Λ + > 117 GeV and Λ − > 110 GeV. The reaction e + e − → γγγ has also been studied and was found to be consistent with the QED prediction. An upper limit on the branching ratio of Z 0 → γγγ has been set at 6.6 × 10 −5 . All the limits are given at 95% confidence level.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

E+ E- PAIR PRODUCTION BY A SYNCHROTRON RADIATION PHOTON ON A COUNTER BEAM ELECTRON. (IN RUSSIAN)

Blinov, A.E. ; Bondar, A.F. ; Bukin, A.D. ; et al.

Yad.Fiz. 45 (1987) 1008-1014, 1987.

Inspire Record 256613 DOI 10.17182/hepdata.17424

None

3 data tables

Table 1

Axis error includes +- 2/2 contribution (Error in counter efficiency determination).

Table 2

Electron momentum distribution.

Table 3

Electron-positron pairs mass distribution.

MEASUREMENT OF THE INCLUSIVE BRANCHING FRACTION tau- ---> tau-neutrino pi- pi0 NEUTRAL MESON(S)

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.

Phys.Rev.Lett. 57 (1986) 1836, 1986.

Inspire Record 233422 DOI 10.17182/hepdata.38106

We measure an inclusive branching fraction of (13.9 ± 2.0−2.2+1.9)% for the decay τ−→ντπ−π0+nh0(n>~1), where h0 is a π0 or an η. The data sample, obtained with the time-projection-chamber detector facility at the SLAC e+e− storage ring PEP, corresponds to an integrated luminosity of 72 pb−1 at 29 GeV center-of-mass energy. The measured branching fraction is somewhat greater than the theoretical prediction and, with errors taken into account, could resolve the present difference between the inclusive and the sum of the exclusive τ± branching fractions into one charged prong.

2 data tables

Table 1

No description provided.

Table 2

No description provided.