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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. C29 (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

1-THRUST distribution.

THRUST-MAJOR distribution.

THRUST-MINOR distribution.

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Determination of alpha-s using the next-to-leading log approximation of QCD

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Z.Phys. C59 (1993) 21-34, 1993.
Inspire Record 354909 DOI 10.17182/hepdata.50115
7 data tables

Thrust distribution corrected for detector acceptance and initial state photon radiation.

Heavy jet mass (RHO) distribution (THRUST definition) corrected for detect or acceptance and initial state photon radiation.

Heavy jet mass (RHOM) distribution (MASS definition) corrected for detectoracceptance and initial state photon radiation.

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Particle multiplicity of unbiased gluon jets from $e^{+} e^{-}$ three jet events

The OPAL collaboration
Eur.Phys.J. C23 (2002) 597-613, 2002.
Inspire Record 565517 DOI 10.17182/hepdata.49742

The charged particle multiplicities of two- and three-jet events from the reaction e+e- -> Z0 -> hadrons are measured for Z0 decays to light quark (uds) flavors. Using recent theoretical expressions to account for biases from event selection, results corresponding to unbiased gluon jets are extracted over a range of jet energies from about 11 to 30 GeV. We find consistency between these results and direct measurements of unbiased gluon jet multiplicity from upsilon and Z0 decays. The unbiased gluon jet data including the direct measurements are compared to corresponding results for quark jets. We perform fits based on analytic expressions for particle multiplicity in jets to determine the ratio r = Ng/Nq of multiplicities between gluon and quark jets as a function of energy. We also determine the ratio of slopes, r(1) = (dNg/dy)/(dNq/dy), and of curvatures, r(2) = (d2Ng/dy2)/(d2Nq/dy2), where y specifies the energy scale. At 30 GeV, we find r = 1.422 +/- 0.051, r(1) = 1.761 +/- 0.071 and r(2) = 1.98 +/- 0.13, where the uncertainties are the statistical and systematic terms added in quadrature. These results are in general agreement with theoretical predictions. In addition, we use the measurements of the energy dependence of Ng and Nq to determine an effective value of the ratio of QCD color factors, CA/CF. Our result, CA/CF = 2.23 +/- 0.14 (total), is consistent with the QCD value of 2.25.

4 data tables

Measurements of the mean charged particle multiplicity of biased two-jet uds flavour events from Z0 decays as a function of the transverse momentum cutoff PT(C=LU) used to separate two- and three-jet events.

Measurements of the mean charged particle multiplicity of three-jet uds flavour 'Y events' from Z0 decays, as a function of the angle THETA1 between the lowest two energy jets. The results for the quark jet scale SQRT(S(C=QQBAR)) and the gluon jet scales PT(C=LU) and PT(C=LE) are also given.

Measurements of the unbiased gluon multiplicity as a function of the energy scale Q=PT(C=LU). The corresponding bins of THETA1 in 'Y events' are also indicated.

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A Measurement of the b quark mass from hadronic Z decays

The ALEPH collaboration Barate, R. ; Decamp, D. ; Ghez, Philippe ; et al.
Eur.Phys.J. C18 (2000) 1-13, 2000.
Inspire Record 531468 DOI 10.17182/hepdata.49909

Hadronic Z decay data taken with the ALEPH detector at LEP1 are used to measure the three-jet rate as well as moments of various event-shape variables. The ratios of the observables obtained from b-tagged events and from an inclusive sample are determined. The mass of the b quark is extracted from a fit to the measured ratios using a next-to-leading order prediction including mass effects. Taking the first moment of the y3 distribution, which is the observable with the smallest hadronization corrections and systematic uncertainties, the result is: mb(MZ) = [3.27+-0.22(stat) +-0.22(exp)+-0.38(had)+-0.16(theo)] GeV/c2. The measured ratio is alternatively employed to test the flavour independence of the strong coupling constant for b and light quarks.

1 data table

No description provided.


Test of the flavor independence of alpha(s) using next-to-leading order calculations for heavy quarks

The OPAL collaboration Abbiendi, G. ; Ackerstaff, K. ; Alexander, G. ; et al.
Eur.Phys.J. C11 (1999) 643-659, 1999.
Inspire Record 498246 DOI 10.17182/hepdata.49192

We present a test of the flavour independence of the strong coupling constant for charm and bottom quarks with respect to light (uds) quarks, based on a hadronic event sample obtained with the OPAL detector at LEP. Five observables related to global event shapes were used to measure alpha_s in three flavour tagged samples (uds, c and b). The event shape distributions were fitted by Order(alpha_s**2) calculations of jet production taking into account mass effects for the c and b quarks. We find: = 0.997 +- 0.038(stat.) +- 0.030(syst.) +- 0.012(theory) and = 0.993 +- 0.008(stat.) +- 0.006(syst.) +- 0.011(theory) for the ratios alpha_s(charm)/alpha_s(uds) and alpha_s(b)/alpha_s(uds) respectively.

1 data table

No description provided.


Test of the flavor independence of alpha-s

The ALEPH collaboration Buskulic, D. ; Casper, D. ; De Bonis, I. ; et al.
Phys.Lett. B355 (1995) 381-393, 1995.
Inspire Record 393416 DOI 10.17182/hepdata.48177
1 data table

No description provided.


QCD studies and determination of alpha-s in e+ e- collisions at s**(1/2) = 161-GeV and 172-GeV

The L3 collaboration Acciarri, M. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett. B404 (1997) 390-402, 1997.
Inspire Record 443563 DOI 10.17182/hepdata.47483
8 data tables

No description provided.

Average jet multiplicity using JADE algorithm.

Average jet multiplicity using Durham algorithm.

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Measurements of alpha-s in e+ e- annihilation at TRISTAN

The TOPAZ collaboration Ohnishi, Y. ; Adachi, I. ; Fujimoto, J. ; et al.
Phys.Lett. B313 (1993) 475-482, 1993.
Inspire Record 361661 DOI 10.17182/hepdata.43784
4 data tables

No description provided.

No description provided.

The exact definition for Y23 see text.

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A Measurement of the QCD color factors and a limit on the light gluino

The ALEPH collaboration Barate, R. ; Buskulic, D. ; Decamp, D. ; et al.
Z.Phys. C76 (1997) 1-14, 1997.
Inspire Record 440051 DOI 10.17182/hepdata.34162
3 data tables

Fit A: using all kinematical distributions. NC, CF, and TF are the color factors for SU(3) group, NF is the number of the active flavors.

Fit B: using all kinematical distributions, but QCD magnitudes for color factors are used: FA(DEF=NC/CF)) = 2.25 and TF/CF = 0.375. NC, CF, and TF are the color factors for SU(3) group, NF is the number of the active flavors.

Fit C: the QCD magnitudes for color factors and NF = 5 are used.


Measurement of event shape and inclusive distributions at S**(1/2) = 130-GeV and 136-GeV

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Z.Phys. C73 (1997) 229-242, 1997.
Inspire Record 424629 DOI 10.17182/hepdata.47715
26 data tables

mean values for event shape variables.

Integral of event shape distribution over the specified interval.

Integral of event shape distribution over the specified interval.

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Measurement of alpha-s in hadronic Z decays using all orders resummed predictions

The ALEPH collaboration Decamp, D. ; Deschizeaux, B. ; Goy, C. ; et al.
Phys.Lett. B284 (1992) 163-176, 1992.
Inspire Record 333334 DOI 10.17182/hepdata.48421
1 data table

Three different methods are used for extraction Alphas value (see text for details). Systematical errors with C=HADR and C=THEOR are due to hadronization correction and theoretical uncertainties.


QCD studies with e+ e- annihilation data at 130-GeV and 136-GeV

The OPAL collaboration Alexander, G. ; Allison, John ; Altekamp, N. ; et al.
Z.Phys. C72 (1996) 191-206, 1996.
Inspire Record 418007 DOI 10.17182/hepdata.47564
23 data tables

Determination of alpha_s.

Multiplicity and high moments.

Tmajor distribution.

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A Search for jet handedness in hadronic Z0 decays

The SLD collaboration Abe, K. ; Abt, I. ; Ahn, C.J. ; et al.
Phys.Rev.Lett. 74 (1995) 1512-1516, 1995.
Inspire Record 378343 DOI 10.17182/hepdata.19666

We have searched for signatures of polarization in hadronic jets from $Z~0 \rightarrow q \bar{q}$ decays using the ``jet handedness'' method. The polar angle asymmetry induced by the high SLC electron-beam polarization was used to separate quark jets from antiquark jets, expected to be left- and right-polarized, respectively. We find no evidence for jet handedness in our global sample or in a sample of light quark jets and we set upper limits at the 95\% C.L. of 0.063 and 0.099 respectively on the magnitude of the analyzing power of the method proposed by Efremov {\it et al.}

1 data table

Polarized E- beam. Events were classified as being of light or heavy flavors based on impact parameters of charged tracks measured in the vertex detector. Jet handedness are measured for helicity-based and chirality-based analysis (seetext). C=95PCT CL indicates the upper limits at the 95 PCT C.L. on the magnitudes.


Measurement of eta production in two and three jet events from hadronic Z decays at LEP

The L3 collaboration Acciarri, M. ; Adam, A. ; Adriani, O. ; et al.
Phys.Lett. B371 (1996) 126-136, 1996.
Inspire Record 404602 DOI 10.17182/hepdata.48038
6 data tables

No description provided.

No description provided.

No description provided.

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A Study of the recombination scheme dependence of jet production rates and of alpha-s (m(Z0)) in hadronic Z0 decays

The OPAL collaboration Akrawy, M.Z. ; Alexander, G. ; Allison, John ; et al.
Z.Phys. C49 (1991) 375-384, 1991.
Inspire Record 299833 DOI 10.17182/hepdata.15085
9 data tables

Jet production rates using the E0 recombination scheme.

Jet production rates using the E recombination scheme.

Jet production rates using the p0 recombination scheme.

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Experimental study of b quark jets in e+ e- annihilation at TRISTAN

The TOPAZ collaboration Nagai, K. ; Enomoto, R. ; Abe, T. ; et al.
Phys.Lett. B278 (1992) 506-510, 1992.
Inspire Record 333342 DOI 10.17182/hepdata.29230
4 data tables

No description provided.

No description provided.

Mean values of jet properties for b-jet sample.

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Properties of hadronic Z decays and test of QCD generators

The ALEPH collaboration Buskulic, D. ; Decamp, D. ; Goy, C. ; et al.
Z.Phys. C55 (1992) 209-234, 1992.
Inspire Record 334577 DOI 10.17182/hepdata.1420
41 data tables

Sphericity distribution.

Sphericity distribution.

Aplanarity distribution.

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Measurement of the strong coupling constant alpha-s from global event shape variables of hadronic Z decays

The ALEPH collaboration Decamp, D. ; Deschizeaux, B. ; Goy, C. ; et al.
Phys.Lett. B255 (1991) 623-633, 1991.
Inspire Record 301661 DOI 10.17182/hepdata.29491
1 data table

The second DSYS error is the theoretical error.


A Comparison of jet production rates on the Z0 resonance to perturbative QCD

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.
Phys.Lett. B247 (1990) 167-176, 1990.
Inspire Record 297698 DOI 10.17182/hepdata.29653
2 data tables

Corrected jet rates.

Second systematic error is theoretical.


First Measurements of Hadronic Decays of the $Z$ Boson

The MARK-II collaboration Abrams, G.S. ; Adolphsen, Chris ; Aleksan, R. ; et al.
Phys.Rev.Lett. 63 (1989) 1558, 1989.
Inspire Record 282670 DOI 10.17182/hepdata.20044
5 data tables

Corrected event shape distributions.

Corrected event shape distributions.

Corrected event shape distributions.

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Comparison of Inclusive Fractional Momentum Distributions of Quark and Gluon Jets Produced in $e^+ e^-$ Annihilation

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys. C45 (1989) 1, 1989.
Inspire Record 277210 DOI 10.17182/hepdata.15299
3 data tables

2 JET data at sqrt(s) = 35 GeV.

3 JET data at sqrt(s) = 22 GeV.

Gluon jet data at sqrt(s) = 11.5 GeV.


Charge Asymmetry of Hadron Jets and Limits on the Compositeness Scales in e$^{+} $e$^{-} \To $q$ \Bar{$q$}$ Reaction at $\Sqrt{$s$}=57$.6-{GeV}

The VENUS collaboration Abe, K. ; Amako, K. ; Arai, Y. ; et al.
Phys.Lett. B232 (1989) 425-430, 1989.
Inspire Record 281245 DOI 10.17182/hepdata.29751
1 data table

Data are fully corrected for detector effects, resolution and radiative effects.


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. B240 (1990) 232-236, 1990.
Inspire Record 296684 DOI 10.17182/hepdata.29690
2 data tables

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

LAMBDA-MSBAR determined from the 3-jet ratio.


Experimental Study of Jet Masses in $e^+ e^-$ Annihilation at $c$.m. Energies Between 12-{GeV} and 43.5-{GeV}

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys. C45 (1989) 11, 1989.
Inspire Record 279165 DOI 10.17182/hepdata.15297
3 data tables

No description provided.

No description provided.

No description provided.


A Study of Jet Production Rates and a Test of QCD on the Z0 Resonance

The OPAL collaboration Akrawy, M.Z. ; Alexander, G. ; Allison, J. ; et al.
Phys.Lett. B235 (1990) 389-398, 1990.
Inspire Record 283783 DOI 10.17182/hepdata.29753
1 data table

Data are corrected for final acceptance and resolution of the detector. No explicit corrections for hadronisation effects are applied.