Magill, S.
Integrated Cross Section
LAMQCD
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Measurement of $\alpha_S$ from Jet Rates in Deep Inelastic Scattering at HERA

The ZEUS collaboration Derrick, M. ; Krakauer, D. ; Magill, S. ; et al.
Phys.Lett.B 363 (1995) 201-216, 1995.
Inspire Record 400436 DOI 10.17182/hepdata.44947

Jet production in deep inelastic scattering for $120<Q~2<3600$GeV$~2$ has been studied using data from an integrated luminosity of 3.2pb$~{-1}$ collected with the ZEUS detector at HERA. Jets are identified with the JADE algorithm. A cut on the angular distribution of parton emission in the $\gamma~*$-parton centre-of-mass system minimises the experimental and theoretical uncertainties in the determination of the jet rates. The jet rates, when compared to ${\cal O}$($\alpha_{s}$~2$) perturbative QCD calculations, allow a precise determination of $\alpha_{s}(Q)$ in three $Q~2$-intervals. The values are consistent with a running of $\alpha_{s}(Q)$, as expected from QCD. Extrapolating to $Q=M_{Z~0}$ yields $\alpha_{s}(M_{Z~0}) = 0.117\pm0.005(stat)~{+0.004}_{-0.005}(syst_{exp}) {\pm0.007}(syst_{theory})$.

3 data tables
Table 1

2+1 jet rate as a function of ycut the jet algorithm cut-off value. Statistical errors only.

Table 2

Measured values of Lambda-QCD in the MS Bar scheme and alpha_s as a function of Q**2. The second systematic uncertainty is related to the theoretical uncertainties .

Table 3

Strong coupling constant alpha_s extrapolated to the Z0 mass.


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
Table 1

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

Table 2

LAMBDA-MSBAR determined from the 3-jet ratio.


rivet Analysis
Measurement of the Total Hadronic Cross-sections in e$^{+} $e$^{-}$ Annihilation and Determination of the Standard Model Parameters

The TOPAZ collaboration Adachi, I. ; Doser, M. ; Enomoto, R. ; et al.
Phys.Lett.B 234 (1990) 525-533, 1990.
Inspire Record 283003 DOI 10.17182/hepdata.29733

We have measured the total e + e − hadronic annihilation cross section at the center of mass energies between 50.0 GeV and 61.4 GeV with the TOPAZ detector at TRISTAN. The full electroweak radiative corrections (up to O(α 3 )) were applied to the data which were analysed together with the published data from PEP and PETRA. We then determined the standard model parameters, M z (the mass of the Z), sin w 2 θ (the Weinberg angle) and Λ MS (the QCD scale parameter) by comparing the experimental data with the prediction of the standard model. The best fit values are M z = 89.2 −1.8 +2.1 GeV/c 2 , sin 2 θ w = 0.233 −0.025 +0.035 and Λ MS = 0.327 −0.206 +0.275 GeV. A constraint is obtained on the heavy top quark mass through the radiative corrections if we take the SLC value of M z (91.1 GeV / c 2 ).

2 data tables
Table 1

No description provided.

Table 2

No description provided.