Inclusive-jet cross sections in NC DIS at HERA and a comparison of the kT, anti-kT and SIScone jet algorithms

The ZEUS collaboration Abramowicz, H. ; Abt, I. ; Adamczyk, L. ; et al.
Phys.Lett.B 691 (2010) 127-137, 2010.
Inspire Record 848883 DOI 10.17182/hepdata.55309

For the first time, differential inclusive-jet cross sections have been measured in neutral current deep inelastic ep scattering using the anti-kT and SIScone algorithms. The measurements were made for boson virtualities Q^2 > 125 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 82 pb^-1 and the jets were identified in the Breit frame. The performance and suitability of the jet algorithms for their use in hadron-like reactions were investigated by comparing the measurements to those performed with the kT algorithm. Next-to-leading-order QCD calculations give a good description of the measurements. Measurements of the ratios of cross sections using different jet algorithms are also presented; the measured ratios are well described by calculations including up to O(alphas^3) terms. Values of alphas(Mz) were extracted from the data; the results are compatible with and have similar precision to the value extracted from the kT analysis.

16 data tables

Measured differential cross section DSIG/DE for inclusive jet production using the anti-KT jet algorithm.

Measured differential cross section DSIG/DE for inclusive jet production using the SIScone jet algorithm.

The measured differential cross section DSIG/DQ**2 for inclusive jet production using the anti-KT jet algorithm.

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Measurement of beauty production in DIS and F_2^bbbar extraction at ZEUS

The ZEUS collaboration Abramowicz, H. ; Abt, I. ; Adamczyk, L. ; et al.
Eur.Phys.J.C 69 (2010) 347-360, 2010.
Inspire Record 855232 DOI 10.17182/hepdata.56879

Beauty production in deep inelastic scattering with events in which a muon and a jet are observed in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb^-1. The fraction of events with beauty quarks in the data was determined using the distribution of the transverse momentum of the muon relative to the jet. The cross section for beauty production was measured in the kinematic range of photon virtuality, Q^2 > 2 Gev^2, and inelasticity, 0.05 < y < 0.7, with the requirement of a muon and a jet. Total and differential cross sections are presented and compared to QCD predictions. The beauty contribution to the structure function F_2 was extracted and is compared to theoretical predictions.

18 data tables

Total visible cross section for BBAR production and decay into MUON+JET.

Measured differential cross section as a function of Q**2.

Measured differential cross section as a function of the muon transverse momentum.

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Scaled momentum spectra in deep inelastic scattering at HERA

The ZEUS collaboration Abramowicz, H. ; Abt, I. ; Adamczyk, L. ; et al.
JHEP 06 (2010) 009, 2010.
Inspire Record 844129 DOI 10.17182/hepdata.55368

Charged particle production has been studied in neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 0.44 fb^-1. Distributions of scaled momenta in the Breit frame are presented for particles in the current fragmentation region. The evolution of these spectra with the photon virtuality, Q^2, is described in the kinematic region 10&lt;Q^2&lt;41000 GeV^2. Next-to-leading-order and modified leading-log-approximation QCD calculations as well as predictions from Monte Carlo models are compared to the data. The results are also compared to e+e- annihilation data. The dependences of the pseudorapidity distribution of the particles on Q^2 and on the energy in the \gamma p system, W, are presented and interpreted in the context of the hypothesis of limiting fragmentation.

26 data tables

Bin averaged scaled momentum spectra in the Q**2 ranges 160 to 320 and 320 to 640 GeV**2.

Bin averaged scaled momentum spectra in the Q**2 ranges 640 to 1280 and 1280 to 2560 GeV**2.

Bin averaged scaled momentum spectra in the Q**2 ranges 2560 to 5120 and 51200 to 10240 GeV**2.

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Combined Measurement and QCD Analysis of the Inclusive ep Scattering Cross Sections at HERA

The H1 & ZEUS collaborations Aaron, F.D. ; Abramowicz, H. ; Abt, I. ; et al.
JHEP 01 (2010) 109, 2010.
Inspire Record 836107 DOI 10.17182/hepdata.58304

A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised ep scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q^2, and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions HERAPDF1.0 with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.

89 data tables

Combined reduced cross section data and F2 for Neutral Current E+ P scattering at Q**2=0.045 GeV**2.

Combined reduced cross section data and F2 for Neutral Current E+ P scattering at Q**2=0.065 GeV**2.

Combined reduced cross section data and F2 for Neutral Current E+ P scattering at Q**2=0.085 GeV**2.

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Measurement of dijet photoproduction for events with a leading neutron at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.
Nucl.Phys.B 827 (2010) 1-33, 2010.
Inspire Record 831440 DOI 10.17182/hepdata.62426

Differential cross sections for dijet photoproduction and this process in association with a leading neutron, e+ + p -> e+ + jet + jet + X (+ n), have been measured with the ZEUS detector at HERA using an integrated luminosity of 40 pb-1. The fraction of dijet events with a leading neutron was studied as a function of different jet and event variables. Single- and double-differential cross sections are presented as a function of the longitudinal fraction of the proton momentum carried by the leading neutron, xL, and of its transverse momentum squared, pT**2. The dijet data are compared to inclusive DIS and photoproduction results/ they are all consistent with a simple pion-exchange model. The neutron yield as a function of xL was found to depend only on the fraction of the proton beam energy going into the forward region, independent of the hard process. No firm conclusion can be drawn on the presence of rescattering effects.

13 data tables

The differential cross section as a function of jet transverse energy for dijet photon production both without and with a leading neutron, together with their ratio.

The differential cross section as a function of jet pseudorapidity for dijet photon production both without and with a leading neutron, together with their ratio.

The differential cross section as a function of x_photon, the fraction of the photon 4-momenta entering the hard scattering, for dijet photon production both without and with a leading neutron, together with their ratio.

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Measurement of isolated photon production in deep inelastic ep scattering

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.
Phys.Lett.B 687 (2010) 16-25, 2010.
Inspire Record 831986 DOI 10.17182/hepdata.54874

Isolated photon production in deep inelastic ep scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 320pb^-1. Measurements were made in the isolated-photon transverse-energy and pseudorapidity ranges 4 &lt; E_T &lt; 15 GeV and -0.7 &lt; eta &lt; 0.9 for exchanged photon virtualities, Q^2, in the range 10 &lt; Q^2 &lt; 350 GeV and for invariant masses of the hadronic system W_X> 5 GeV. Differential cross sections are presented for inclusive isolated photon production as functions of Q^2, x, E_T and eta. Leading-logarithm parton-shower Monte Carlo simulations and perturbative QCD predictions give a reasonable description of the data over most of the kinematic range.

6 data tables

Measured integrated cross section.

Measured differential cross section DSIG/DET.

Measured differential cross section DSIG/DETARAP.

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Measurement of J/psi photoproduction at large momentum transfer at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.
JHEP 05 (2010) 085, 2010.
Inspire Record 833339 DOI 10.17182/hepdata.55178

The proton-dissociative diffractive photoproduction of J/psi mesons has been studied in ep collisions with the ZEUS detector at HERA using an integrated luminosity of 112 pb^-1. The cross section is presented as a function of the photon-proton centre-of-mass energy and of the squared four-momentum transfer at the proton vertex. The results are compared to perturbative QCD calculations.

14 data tables

The differential cross section DSIG/DT as a function of T.

The differential cross section DSIG/DT as a function of W in the ABS(T) range 2.0 to 2.5 GeV**2.

The differential cross section DSIG/DT as a function of W in the ABS(T) range 2.5 to 3.0 GeV**2.

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Measurement of charged current deep inelastic scattering cross sections with a longitudinally polarised electron beam at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.
Eur.Phys.J.C 61 (2009) 223-235, 2009.
Inspire Record 810120 DOI 10.17182/hepdata.51622

Measurements of the cross sections for charged current deep inelastic scattering in e-p collisions with longitudinally polarised electron beams are presented. The measurements are based on a data sample with an integrated luminosity of 175 pb-1 collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is given for positively and negatively polarised electron beams. The differential cross-sections dsigma/dQ2, dsigma/dx and dsigma/dy are presented for Q2>200 GeV2. The double-differential cross-section d2sigma/dxdQ2 is presented in the kinematic range 280&lt;Q2&lt;30000 GeV2 and 0.015&lt;x&lt;0.65. The measured cross sections are compared with the predictions of the Standard Model.

38 data tables

Total cross section for CC DIS events for two values of the longitudinal polarization of the electron beam.

Total cross section for CC DIS events as a function of the longitudinal polarization of the electron beam.

Differential cross section DSIG/DQ**2 for the two values of longitudinal polarization of the electron beam.

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Measurement of the Longitudinal Proton Structure Function at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.
Phys.Lett.B 682 (2009) 8-22, 2009.
Inspire Record 817462 DOI 10.17182/hepdata.53740

The reduced cross sections for ep deep inelastic scattering have been measured with the ZEUS detector at HERA at three different centre-of-mass energies, 318, 251 and 225 GeV. From the cross sections, measured double differentially in Bjorken x and the virtuality, Q^2, the proton structure functions FL and F2 have been extracted in the region 5*10^-4 &lt; x &lt;0.007 and 20 &lt; Q^2 &lt; 130 GeV^2.

50 data tables

The reduced cross section at Q**2 = 24 GeV**2 for centre-of-mass energy 318.

The reduced cross section at Q**2 = 32 GeV**2 for centre-of-mass energy 318.

The reduced cross section at Q**2 = 45 GeV**2 for centre-of-mass energy 318.

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Scaled momentum distributions of charged particles in dijet photoproduction at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.
JHEP 08 (2009) 077, 2009.
Inspire Record 818528 DOI 10.17182/hepdata.52943

The scaled momentum distributions of charged particles in jets have been measured for dijet photoproduction with the ZEUS detector at HERA using an integrated luminosity of 359 pb-1. The distributions are compared to predictions based on perturbative QCD carried out in the framework of the modified leading-logarithmic approximation (MLLA) and assuming local parton-hadron duality (LPHD). The universal MLLA scale, Lambda_eff, and the LPHD parameter, kappa^ch, are extracted.

15 data tables

Distribution of multiplicity of charged particles in a jet as a function of LN(1/X) for mean jet energy 19 GeV and jet cone opening angle 0.23.

Distribution of multiplicity of charged particles in a jet as a function of LN(1/X) for mean jet energy 23 GeV and jet cone opening angle 0.23.

Distribution of multiplicity of charged particles in a jet as a function of LN(1/X) for mean jet energy 28 GeV and jet cone opening angle 0.23.

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