Apadula, N.
E+ E- --> 3JET
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rivet Analysis
A study of the energy evolution of event shape distributions and their means with the DELPHI detector at LEP.

The DELPHI collaboration Abdallah, J. ; Abreu, P. ; Adam, W. ; et al.
Eur.Phys.J.C 29 (2003) 285-312, 2003.
Inspire Record 620250 DOI 10.17182/hepdata.13029

Infrared and collinear safe event shape distributions and their mean values are determined in e+e- collisions at centre-of-mass energies between 45 and 202 GeV. A phenomenological analysis based on power correction models including hadron mass effects for both differential distributions and mean values is presented. Using power corrections, alpha_s is extracted from the mean values and shapes. In an alternative approach, renormalisation group invariance (RGI) is used as an explicit constraint, leading to a consistent description of mean values without the need for sizeable power corrections. The QCD beta-function is precisely measured using this approach. From the DELPHI data on Thrust, including data from low energy experiments, one finds beta_0 = 7.86 +/- 0.32 for the one loop coefficient of the beta-function or, assuming QCD, n_f = 4.75 +/- 0.44 for the number of active flavours. These values agree well with the QCD expectation of beta_0=7.67 and n_f=5. A direct measurement of the full logarithmic energy slope excludes light gluinos with a mass below 5 GeV.

71 data tables
Table 1

1-THRUST distribution.

Table 2

THRUST-MAJOR distribution.

Table 3

THRUST-MINOR distribution.

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Quark and gluon jet properties in symmetric three-jet events

The ALEPH collaboration Buskulic, D. ; Casper, D. ; De Bonis, I. ; et al.
Phys.Lett.B 384 (1996) 96008490 353-364, 1996.
Inspire Record 404562 DOI 10.17182/hepdata.48015

Quark and gluon jets with the same energy, 24 GeV, are compared in symmetric three-jet configurations from hadronic Z decays observed by the ALEPH detector. Jets are defined using the Durham algorithm. Gluon jets are identified using an anti-tag on b jets, based on a track impact parameter method. The comparison of gluon and mixed flavour quark jets shows that gluon jets have a softer fragmentation function, a larger angular width and a higher particle multiplicity, Evidence is presented which shows that the corresponding differences between gluon and b jets are significantly smaller. In a statistically limited comparison the multiplicity in c jets was found to be comparable with that observed for the jets of mixed quark flavour.

2 data tables
Table 1

B-jets are identified with the lepton-tag analysis.

Table 2

The same kinematics as in the table 1.


Measurement of three jet distributions sensitive to the gluon spin in e+ e- annihilations at S**(1/2) = 91-GeV

The OPAL collaboration Alexander, G. ; Allison, John ; Allport, P.P. ; et al.
Z.Phys.C 52 (1991) 543-550, 1991.
Inspire Record 317142 DOI 10.17182/hepdata.14852

None

4 data tables
Table 1

Data at Parton level.

Table 2

Ratio data/(Monte Carlo) at Parton level.

Table 3

Data at Parton level.. Distribution of Ellis-Karliner angle.

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