E+ E- --> JET X
DSIG/DC-PARAMETER
Max results
Sort by Reverse order

Showing 3 of 3 results

QCD studies in e+ e- annihilation from 30-GeV to 189-GeV

The L3 collaboration Acciarri, M. ; Achard, P. ; Adriani, O. ; et al.
Phys.Lett.B 489 (2000) 65-80, 2000.
Inspire Record 527988 DOI 10.17182/hepdata.21126

We present results obtained from a study of the structure of hadronic events recorded by the L3 detector at various centre-of-mass energies. The distributions of event shape variables and the energy dependence of their mean values are measured from 30GeV to 189GeV and compared with various QCD models. The energy dependence of the moments of event shape variables is used to test a power law ansatz for the non-perturbative component. We obtain a universal value of the non-perturbative parameter alpha_0 = 0.537 +/- 0.073. From a comparison with resummed O(alpha_s^2) QCD calculations, we determine the strong coupling constant at each of the selected energies. The measurements demonstrate the running of alpha_s as expected in QCD with a value of alpha_s(m_Z) = 0.1215 +/- 0.0012 (exp) +/- 0.0061 (th).

22 data tables
Table 1

Distribution for THRUST at c.m. energy 189 GeV.

Table 2

Distribution for Heavy Jet Mass at c.m. energy 189 GeV.

Table 3

Distribution for Total Jet Broadening at c.m. energy 189 GeV.

More…

Determination of $alpha_{s}$ in second order {QCD} from hadronic $Z$ decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.
Z.Phys.C 54 (1992) 55-74, 1992.
Inspire Record 333272 DOI 10.17182/hepdata.14603

Distributions of event shape variables obtained from 120600 hadronicZ decays measured with the DELPHI detector are compared to the predictions of QCD based event generators. Values of the strong coupling constant αs are derived as a function of the renormalization scale from a quantitative analysis of eight hadronic distributions. The final result, αs(MZ), is based on second order perturbation theory and uses two hadronization corrections, one computed with a parton shower model and the other with a QCD matrix element model.

9 data tables
Table 1

Experimental differential Thrust distributions.

Table 2

Experimental differential Oblateness distributions.

Table 3

Experimental differential C-parameter distributions.

More…

A Global determination of alpha-s (M(z0)) at LEP

The OPAL collaboration Acton, P.D. ; Alexander, G. ; Allison, John ; et al.
Z.Phys.C 55 (1992) 1-24, 1992.
Inspire Record 333079 DOI 10.17182/hepdata.14606

The value of the strong coupling constant,$$\alpha _s (M_{Z^0 } )$$, is determined from a study of 15 d

16 data tables
Table 1

Differential jet mass distribution for the heavier jet using method T. The data are corrected for the finite acceptance and resolution of the detector and for initial state photon radiation.

Table 2

Differential jet mass distribution for the jet mass difference using methodT. The data are corrected for the finite acceptance and resolution of the detec tor and for initial state photon radiation.

Table 3

Differential jet mass distribution for the heavier jet using method M. The data are corrected for the finite acceptance and resolution of the detector and for initial state photon radiation.

More…