Helland, Jerome A.
E- P --> 2JET E- X
Neutral Current
DSIG/DETARAP
[100.0, 1000.0]
Max results
Sort by Reverse order

Showing 2 of 2 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.

More…

Dijet cross-sections in photoproduction at HERA

The ZEUS collaboration Derrick, M. ; Krakauer, D. ; Magill, S. ; et al.
Phys.Lett.B 348 (1995) 665-680, 1995.
Inspire Record 392980 DOI 10.17182/hepdata.44999

Dijet production by almost real photons has been studied at HERA with the ZEUS detector. Jets have been identified using the cone algorithm. A cut on xg, the fraction of the photon energy participating in the production of the two jets of highest transverse energy, is used to define cross sections sensitive to the parton distributions in the proton and in the photon. The dependence of the dijet cross sections on pseudorapidity has been measured for xg $\ge 0.75$ and xg $< 0.75$. The former is sensitive to the gluon momentum density in the proton. The latter is sensitive to the gluon in the photon. The cross sections are corrected for detector acceptance and compared to leading order QCD calculations.

2 data tables
Table 1

Direct photon di-jet cross section.. Data are for two (or more) jets.. Second systematic error is due to energy scale uncertainty.

Table 2

Resolved photon di-jet cross section.. Data are for two (or more) jets.. Second systematic error is due to energy scale uncertainty.