20-27 July 2011
Alpes Congrès - Alpexpo
Europe/Paris timezone

Inclusive e-p cross sections at HERA and determinations of F_L

21 Jul 2011, 14:45
15m
Bayard (Alpes Congrès - Alpexpo)

Bayard

Alpes Congrès - Alpexpo

Parallel session talk QCD

Speaker

Vladimir Chekelian

Description

A combination of the inclusive cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current deep-inelastic ep scattering at HERA is presented. The combination uses data from unpolarised ep scattering taken during the HERA-I phase as well as measurements with longitudinally polarised electron or positron beams from the HERA-II running period. The combination method takes the correlations of systematic uncertainties into account. The inclusion of the large HERA-II data set leads to an improved uncertainty especially at large four momentum transfer squared Q2. A combination is presented of the inclusive deep inelastic cross sections measured in neutral and charged current unpolarised $e^{\pm}p$ scattering at HERA during the period $1994$-$2000$. 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. A combination of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations for ep scattering with nominal and reduced proton-beam energies, Ep=920 GeV, Ep=460 GeV and 575 GeV, is presented. The combination method used takes the correlations of systematic uncertainties into account, resulting in improved accuracy. From the combined data the proton structure function, FL, is extracted in the region of 2.5<800 GeV2. Finally, a measurement is presented of the inclusive neutral current e\pm p scattering cross section using data collected by the H1 experiment at HERA during the years 2003 to 2007 with proton beam energies Ep of 920, 575, and 460 GeV. The kinematic range of the measurement covers low absolute four-momentum transfers squared, 1.5 GeV2 < Q2 < 120 GeV2, small values of Bjorken x, 2.9 \cdot 10-5 < x < 0.01, and extends to high inelasticity up to y = 0.85. The structure function FL is measured by combining the new results with previously published H1 data at Ep = 920 GeV and Ep = 820 GeV. The new measurements are used to test several phenomenological and QCD models applicable in this low Q2 and low x kinematic domain.

Primary author

Dr Olaf BEHNKE (DESY)

Presentation Materials