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Claudia Glasman

Publications and source records attributed to Claudia Glasman.

12 recordsLinked to original sources
arXiv2010

Jet cross sections in neutral current deep inelastic scattering at ZEUS and determination of alphas

The latest results on jet cross sections in neutral current deep inelastic $ep$ scattering from the ZEUS Collaboration are presented. The new results were used to perform stringent tests of perturbative QCD and extract precise values of the strong coupling. Also, the measurements have the potential to constrain further the parton distribution functions in the proton if included in QCD fits.

hep-ex↗
arXiv2008

Jet substructure at HERA

A review is presented of jet substructure measurements from the H1 and ZEUS Collaborations at HERA. The results presented include tests of perturbative QCD, comparison of the properties of quark and gluon jets, the comparison of the pattern of QCD radiation in different hard scattering processes, determination of the strong coupling and studies of the underlying subprocesses dynamics and of the pattern of parton radiation.

hep-ex↗
arXiv2007

Precision measurements of alphas at HERA

Recent determinations of alphas(Mz) from the H1 and ZEUS Collaborations using inclusive-jet cross-section measurements in neutral current deep inelastic scattering at high Q2 are presented. A combined value of alphas(mz)=0.1198 +- 0.0019 (exp.) +- 0.0026 (th.) was obtained from these measurements. The determinations of alphas at various scales clearly show the running of the coupling from HERA jet data alone and in agreement with the prediction of QCD.

hep-ex↗
arXiv2005

Event shapes and subjet distributions at HERA

Recent results on subjet distributions from ZEUS are presented. The measured normalised cross sections were used to study the pattern of parton radiation. The comparison of the measurements with leading-logarithm parton-shower Monte Carlo models and perturbative QCD calculations shows a good agreement between data and predictions. Results on event-shape mean values and distributions are also presented. These measurements were used to test the predictions of the power-correction model for hadronisation. A universal value, within 10%, of the effective parameter alpha_0 of the model was obtained.

hep-ex↗
arXiv2005

Precision Measurements of alphas at HERA

The precision measurements of the strong coupling constant, alphas, and its energy-scale dependence carried out at HERA by the H1 and ZEUS Collaborations are reviewed. An average value of alphas(Mz) = 0.1186 +- 0.0011 (exp.) +- 0.0050 (th.) is obtained from these measurements. The combined HERA determinations of the energy-scale dependence of alphas clearly show the running of alphas from jet data alone and are in agreement with the running of the coupling as predicted by QCD.

hep-ex↗
arXiv2000

The Structure of the Virtual Photon

Measurements of dijet cross sections for virtual photons are presented as a function of $\xo$, the fraction of the virtual photon energy invested in the production of the dijet system, using the ZEUS detector. Comparisons to QCD predictions show that a resolved photon component is needed to describe the data up to values of the photon virtuality comparable to the scale of the interaction.

hep-ex↗
arXiv2000

Jet Substructure at HERA

Measurements of jet shapes and subjet multiplicities in photoproduction performed by ZEUS are presented and compared to leading-logarithm parton-shower Monte Carlo models. The predicted differences on the size of gluon- and quark-initiated jets are used to select samples to study the dynamics of the subprocesses.

hep-ex↗
arXiv1999

QCD Tests at HERA

Measurements of inclusive jet, dijet and three-jet cross sections in photon-proton interactions are presented. These measurements provide new tests of QCD, constrain the parton densities of the photon, and allow searches for new physics. Measurements of the mean subjet multiplicity are reported and used to test the differences between quark and gluon jets.

hep-ex↗
arXiv1999

Inclusive hard processes in photon-photon and photon-proton interactions

Measurements of jet, prompt photon, high-pT hadron and heavy quark production in photon-induced processes provide tests of QCD and are sensitive to the photon parton densities. A review of the latest experimental results in photon-photon and photon-proton interactions is presented. Next-to-leading-order QCD calculations for these measurements are discussed.

hep-ex↗
arXiv1999

Jet Physics at HERA

Measurements of inclusive jet and dijet cross sections in photoproduction and deep inelastic scattering are presented. These measurements provide new tests of QCD, constrain the parton densities of the proton and the photon, and allow the search for new physics. Measurements of jet shapes are reported and used to test the differences between quark and gluon jets.

hep-ex↗
arXiv1997

Jet Production at HERA

Studies on the structure of the photon are presented by means of the extraction of a leading order effective parton distribution in the photon and measurements of inclusive jet differential cross sections in photoproduction. Measurements of the internal structure of jets have been performed and are also presented as a function of the transverse energy and pseudorapidity of the jets. Dijet cross sections have been measured as a function of the dijet mass and centre-of-mass scattering angle.

hep-ex↗
arXiv1997

Jet Cross Sections and Jet Shapes in Photoproduction at HERA

Studies on the structure of the photon are presented by means of the extraction of a leading order effective parton distribution in the photon and measurements of inclusive jet differential cross sections in photoproduction. Measurements of the internal structure of jets have been performed and are also presented as a function of the transverse energy and pseudorapidity of the jets.

hep-ex↗