Inclusive deep inelastic scattering at high Q 2 with longitudinally polarised lepton beams at HERA

Abstract

Inclusive e ± p single and double differential cross sections for neutral and charged current deep inelastic scattering processes are measured with the H1 detector at HERA. The data were taken at a centre-of-mass energy of √ s = 319 GeV with a total integrated luminosity of 333.7 pb −1 shared between two lepton beam charges and two longitudinal lepton polarisation modes. The differential cross sections are measured in the range of negative fourmomentum transfer squared, Q 2 , between 60 and 50 000 GeV 2 , and Bjorken x between 0.0008 and 0.65. The measurements are combined with earlier published unpolarised H1 data to improve statistical precision and used to determine the structure function xF γZ 3 . A measurement of the neutral current parity violating structure function F γZ 2 is presented for the first time. The polarisation dependence of the charged current total cross section is also measured. The new measurements are well described by a next-to-leading order QCD fit based on all published H1 inclusive cross section data which are used to extract the parton distribution functions of the proton.

Parton distributions for the LHC run II

“…In NNPDF3.0, several new datasets have been included. First, we have included all relevant inclusive cross section measurements from HERA Run II [51][52][53][54]. This includes the complete set of inclusive measurements from H1 and ZEUS, as well as new H1 data at low Q 2 and high-y.…”

“…We begin with the new deep-inelastic scattering data. In this work we have supplemented the combined HERA-I dataset with the inclusion of all the relevant HERA-II inclusive cross sections measurements from H1 and ZEUS [51][52][53][54]. These data improve the statistical and systematic precision of medium-and high-Q 2 data from the HERA-I run, and thus provide valuable information for quarks at medium and large x.…”

“…From the H1 experiment, we have included the new high-Q 2 data from the HERA-II run [51], which covers the large Q 2 region, 60 ≤ Q 2 ≤ 5 10 4 GeV 2 , with improved statistical and systematic precision in comparison to Run-I. These data, taken at the default proton beam energy of E p = 920 GeV used in most of the HERA-II run, have been supplemented with inclusive cross-section measurements performed at lower center-of-mass energies [52], obtained with proton beam energies of E p = 575 GeV and E p = 460 GeV.…”

Charm production and QCD analysis at HERA and LHC

“…Correlated uncertainties are treated using nuisanceparameter representation [228]. The χ 2 -function includes an additional logarithmic term which is relevant when the estimated statistical and uncorrelated systematic uncertainties of the data are rescaled during the fit [231]. The uncertainties were evaluated following the strategy of [2,60].…”

Parton distribution benchmarking with LHC data

“…The HERAPDF collaboration have released the HERAPDF1.5 NNLO PDF set [10,11], which in addition to the combined HERA-I dataset uses the inclusive HERA-II data from H1 [12] and ZEUS [13]. 1 The latest release from NNPDF is the NNPDF2.3 [14] set.…”