Measurements of the structure of quark and gluon jets in hadronic Z decays.

The ALEPH collaboration Barate, R. ; Buskulic, D. ; Decamp, D. ; et al.
Eur.Phys.J.C 17 (2000) 1-18, 2000.
Inspire Record 467225 DOI 10.17182/hepdata.49549

An experimental investigation of the structure of identified quark and gluon jets is presented. Observables related to both the global and internal structure of jets are measured; this allows for test

6 data tables match query

The measured jet broadening distributions (B) in quark and gluon jets seperately.

Measured distributions of -LN(Y2), where Y2 is the differential one-subjet rate, that is the value of the subjet scale parameter where 2 jets appear from the single jet.

The mean subjet multiplicity (-1) for gluon jets and quark jets for different values of the subject resolution parameter Y0.

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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.C 18 (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 match query

No description provided.


Comparison of deep inelastic electron photon scattering data with the HERWIG and PHOJET Monte Carlo models.

The ALEPH & L3 & OPAL & LEP Working Group collaborations Achard, P. ; Andreev, V. ; Braccini, S. ; et al.
Eur.Phys.J.C 23 (2002) 201-223, 2002.
Inspire Record 535230 DOI 10.17182/hepdata.49877

Deep inelastic electron-photon scattering is studied in the Q**2 range from 1.2 to 30 GeV**2 using the LEP1 data taken with the ALEPH, L3 and OPAL detectors at centre-of-mass energies close to the mass of the Z boson. Distributions of the measured hadronic final state are corrected to the hadron level and compared to the predictions of the HERWIG and PHOJET Monte Carlo models. For large regions in most of the distributions studied the results of the different experiments agree with one another. However, significant differences are found between the data and the models. Therefore the combined LEP data serve as an important input to improve on the Monte Carlo models.

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The individual differential cross sections (DSIG/DW) in the low Q**2 regions for the three experiments.. The data are corrected using the HERWIG-kt model.

The combined differential cross sections (DSIG/DW) separately for the low and high Q**2 regions. The data are corrected using the HERWIG-kt model.

The combined differential cross sections (DSIG/DW) separately for the low and high Q**2 regions. The data are corrected using the PHOJET model.

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Measurement of the b forward-backward asymmetry and mixing using high-p(T) leptons.

The ALEPH collaboration Buskulic, D. ; De Bonis, I. ; Decamp, D. ; et al.
Phys.Lett.B 384 (1996) 96009264 414-426, 1996.
Inspire Record 419905 DOI 10.17182/hepdata.47806

The B<sup loc="post">0</sup> - B̄<sup loc="post">0</sup> average mixing parameter <math altimg="si1.gif"><rm><ovl type="bar" style="s">χ</ovl></rm></math> and b forward-backward asymmetry AFB<sup loc="post">0</sup>(b) are measured from a sample of about 4 200 000 Z → qq̄ events recorded with the ALEPH detector at LEP in the years 1990–1995. High transverse momentum electrons and muons produced in b semileptonic decays provide the tag of the quark flavour and of its charge. The average mixing parameter and the pole b asymmetry are measured to be <math altimg="si1.gif"><rm><ovl type="bar" style="s">χ</ovl></rm></math> = 0.1246 ± 0.0051stat ± 0.0052syst, AFB<sup loc="post">0</sup>(b) = 0.1008 ± 0.0043stat ± 0.0028syst. The value of sin<sup loc="post">2</sup>θw<sup loc="post">eff</sup> = 0.23198 ± 0.00092 is extracted from the asymmetry measurement.

2 data tables match query

ASYM(N=FB,C=OBSERVED) is observed asymmetry including BQ, CQ and backround.

No description provided.


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 match query

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

The same kinematics as in the table 1.


Measurement of the Cross Section for open b-Quark Production in Two-Photon Interactions at LEP

The ALEPH collaboration Schael, S. ; Barate, R. ; Bruneliere, R. ; et al.
JHEP 09 (2007) 102, 2007.
Inspire Record 753710 DOI 10.17182/hepdata.48802

Inclusive beauty-quark production in two-photon collisions has been measured at LEP using an integrated luminosity of 698 pb-1 collected by the ALEPH detector with sqrt(s) between 130 and 209 GeV. The b quarks were identified using lifetime information. The cross section is found to be sigma(e+ e- --> e+ e- b \bar{b} X) = (5.4 +/- 0.8 (stat) +/- 0.8 (syst)) pb which is consistent with Next-to-Leading Order QCD.

1 data table match query

Cross section for the process E+ E- --> E+ E- BQUARK BQUARKBAR X.


Studies of QCD in e+ e- --> hadrons at E(cm) = 130-GeV and 136-GeV.

The ALEPH collaboration Buskulic, D. ; De Bonis, I. ; Decamp, D. ; et al.
Z.Phys.C 73 (1997) 409-420, 1997.
Inspire Record 421546 DOI 10.17182/hepdata.47802

None

8 data tables match query

Inclusive charged particle distribution as a function of XP.

Inclusive charged particle distribution as a function of rapidity (YRAP).

Inclusive charged particle distribution as a function of PT in the event plane.

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Measurement of hadron and lepton pair production from e+ e- annihilation at center-of-mass energies of 130-GeV and 136-GeV

The ALEPH collaboration Buskulic, D. ; De Bonis, I. ; Decamp, D. ; et al.
Phys.Lett.B 378 (1996) 373-384, 1996.
Inspire Record 421552 DOI 10.17182/hepdata.47801

Hadronic and leptonic cross-sections and forward-backward asymmetries are measured using 5.7 pb −1 of data taken with the ALEPH detector at LEP at centre-of-mass energies of 130 and 136 GeV. The results agree with Standard Model expectations. The measurement of hadronic cross-sections far away from the Z resonance improves the determination of the interference between photon and Z exchange. Constraints on models with extra Z bosons are presented.

12 data tables match query

Data with loose SPRIME cut.

Data with tight SPRIME cut.

Data with loose SPRIME cut.

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First measurement of the quark to photon fragmentation function

The ALEPH collaboration Buskulic, D. ; Casper, D. ; De Bonis, I. ; et al.
Z.Phys.C 69 (1996) 365-378, 1996.
Inspire Record 398193 DOI 10.17182/hepdata.12261

Earlier measurements at LEP of isolated hard photons in hadronic Z decays, attributed to radiation from primary quark pairs, have been extended in the ALEPH experiment to include hard photon productioninside hadron jets. Events are selected where all particles combine democratically to form hadron jets, one of which contains a photon with a fractional energyz≥0.7. After statistical subtraction of non-prompt photons, the quark-to-photon fragmentation function,D(z), is extracted directly from the measured 2-jet rate. By taking into account the perturbative contributions toD(z) obtained from anO(ααs) QCD calculation, the unknown non-perturbative component ofD(z) is then determined at highz. Provided due account is taken of hadronization effects nearz=1, a good description of the other event topologies is then found.

16 data tables match query

2-jet events. Variable Z has been defined as E(gamma)/(E(gamma)+E(had)), where E(gamma) is the energy of the hard photon in 'photon-jet', E(had) is the energy of the rest hadrons in jet. Ycut is jet resolution parameter (see paper).

2-jet events. Variable Z has been defined as E(gamma)/(E(gamma)+E(had)), where E(gamma) is the energy of the hard photon in 'photon-jet', E(had) is the energy of the rest hadrons in jet. Ycut is jet resolution parameter (see paper).

2-jet events. Variable Z has been defined as E(gamma)/(E(gamma)+E(had)), where E(gamma) is the energy of the hard photon in 'photon-jet', E(had) is the energy of the rest hadrons in jet. Ycut is jet resolution parameter (see paper).

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Measurement of alpha-s from scaling violations in fragmentation functions in e+ e- annihilation

The ALEPH collaboration Buskulic, D. ; Casper, D. ; De Bonis, I. ; et al.
Phys.Lett.B 357 (1995) 487-499, 1995.
Inspire Record 398195 DOI 10.17182/hepdata.47843

A study of scaling violations in fragmentation functions performed by the ALEPH collaboration at LEP is presented. Data samples enriched in uds, c, b and gluon jets, respectively, together with measurements of the longitudinal and transverse inclusive cross sections are used to extract the fragmentation function for the gluon and for each flavour. The measurements are compared to data from experiments at energies between 22 GeV and 91 GeV and scaling violations consistent with QCD predictions are observed. From this, a measurement of the strong coupling constant α s ( Mz ) = 0.126 ±0.009 is obtained.

4 data tables match query

No description provided.

No description provided.

No description provided.

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