HEPData Search

Showing 10 of 13 results

Substructure dependence of jet cross sections at HERA and determination of alpha(s).

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Loizides, J.H. ; et al.

Nucl.Phys.B 700 (2004) 3-50, 2004.

Inspire Record 650732 DOI 10.17182/hepdata.46136

Jet substructure and differential cross sections for jets produced in the photoproduction and deep inelastic ep scattering regimes have been measured with the ZEUS detector at HERA using an integrated luminosity of 82.2 pb-1. The substructure of jets has been studied in terms of the jet shape and subjet multiplicity for jets with transverse energies Et(jet) > 17 GeV. The data are well described by the QCD calculations. The jet shape and subjet multiplicity are used to tag gluon- and quark-initiated jets. Jet cross sections as functions of Et(jet), jet pseudorapidity, the jet-jet scattering angle, dijet invariant mass and the fraction of the photon energy carried by the dijet system are presented for gluon- and quark-tagged jets. The data exhibit the behaviour expected from the underlying parton dynamics. A value of alphas(Mz) of alphas(Mz) = 0.1176 +-0.0009(stat.) -0.0026 +0.0009 (exp.) -0.0072 +0.0091 (th.) was extracted from the measurements of jet shapes in deep inelastic scattering.

31 data tables

Table 1

Measured mean integrated jet shape corrected to the hadron level in photoproduction with ET(C=JET) > 17 GeV.

Table 2

Measured mean integrated jet shape corrected to the hadron level in photoproduction with ET(C=JET) > 17 GeV.

Table 3

Measured mean integrated jet shape corrected to the hadron level in photoproduction with -1 < ETARAP(C=JET) < 2.5.

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rivet Analysis
A Study of the fragmentation of quarks in e- p collisions at HERA

The H1 collaboration Aid, S. ; Andreev, V. ; Andrieu, B. ; et al.

Nucl.Phys.B 445 (1995) 3-21, 1995.

Inspire Record 394793 DOI 10.17182/hepdata.44978

Deep inelastic scattering (DIS) events, selected from 1993 data taken by the H1 experiment at HERA, are studied in the Breit frame of reference. The fragmentation function of the quark is compared with those of \ee data. It is shown that certain aspects of the quarks emerging from within the proton in \ep interactions are essentially the same as those of quarks pair-created from the vacuum in \ee annihilation. The measured area, peak position and widthof the fragmentation function show that the kinematic evolution variable, equivalent to the \ee squared centre of mass energy, is in the Breit frame the invariant square of the four-momentum transfer. We comment on the extent to which we have evidence for coherence effects in parton showers.

6 data tables

Table 1

Distribution of the cosine of the Breit frame polar angle for data with the Breit frame energy flow selection. Statistical errors only.

Table 2

Distribution of the cosine of the Breit frame polar angle for data before the Breit frame energy flow selection. Statistical errors only.

Table 3

The fragmentation function for the current hemisphere of the Breit frame. Data are Breit frame energy flow selected only. Statistical errors only.

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A Model independent measurement of quark and gluon jet properties and differences

The OPAL collaboration Akers, R. ; Alexander, G. ; Allison, John ; et al.

Z.Phys.C 68 (1995) 179-202, 1995.

Inspire Record 396179 DOI 10.17182/hepdata.47862

None

3 data tables

Table 1

THETA is the angle between hadron and jet's axis. CONST is the parameter used in jet's definition (see text).

Table 2

CONST is the parameter used in jet's definition (see text).

Table 3

CONST is the parameter used in jet's definition (see text).

Rescattering probed by the emission of slow target associated particles in high-energy heavy ion interactions

The EMU01 collaboration Adamovich, M.I ; Aggarwal, M.M ; Alexandrov, Y.A ; et al.

Phys.Lett.B 363 (1995) 230-236, 1995.

Inspire Record 406952 DOI 10.17182/hepdata.28438

In this letter the distribution of slow target associated particles emitted in Au + Emulsion interactions at 11.6 A GeV/ c is studied. The three models RQMD, FRITIOF and VENUS are used for comparisons and especially their treatment of rescattering is investigated.

6 data tables

Table 1

No description provided.

Table 2

PROJECTILE ASSOCIATED HE-FRAGMENTS.

Table 3

No description provided.

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rivet Analysis
Production of Lambda and Lambda anti-Lambda correlations in the hadronic decays of the Z0

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.

Phys.Lett.B 318 (1993) 249-262, 1993.

Inspire Record 360638 DOI 10.17182/hepdata.48369

An analysis of the production of the Λ baryon in the hadronic decays of the Z 0 is presented, based on about 993K multihadronic events collected by the DELPHI detector at LEP during 1991 and 1992. The differencial cross section of the Λ and the correlations between Λ and Λ produced in the same event are compared to current models, based both on string fragmentation and on cluster decay. The predictions of the string fragmentation model are found to give satisfactory agreements with the data, clearly better than those of the cluster model.

6 data tables

Table 1

No description provided.

Table 2

Combined LAMBDA and LAMBDABAR multiplicity.

Table 3

Errors contain systematic uncertainties.

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Central Collisions of 800-{GeV} Protons With Ag / Br Nuclei in Nuclear Emulsion

The BATON ROUGE-KRAKOW-MOSCOW-TASHKENT collaboration Abduzhamilov, A. ; Barbier, L.M. ; Chernova, L.P. ; et al.

Phys.Rev.D 39 (1989) 86-91, 1989.

Inspire Record 280844 DOI 10.17182/hepdata.3813

Central collisions of 800-GeV protons with the heavy components of nuclear emulsion, Ag107 and Br80, have been investigated to determine the characteristics of small-impact-parameter collisions and, by comparison with the analysis of inclusive proton-emulsion inelastic interactions and inelastic proton-nucleon collisions, to study the dependence of the interaction process on the mean number of intranuclear collisions 〈ν〉. The data are also compared with the results obtained in proton-emulsion collisions, both central and inclusive, at 200 GeV. The variations in the secondary-particle multiplicities and the normalized pseudorapidity density correlate with 〈ν〉 and demonstrate that proton-nucleus interactions, both central and inclusive, can be described adequately by the incoherent superposition of proton-nucleon collisions.

5 data tables

Table 1

NUCLEUS IS AVERAGE NUCLEUS OF EMULSION.

Table 2

NUCLEUS IS AVERAGE NUCLEUS OF EMULSION.

Table 3

NUCLEUS IS AVERAGE NUCLEUS OF EMULSION.