1,721,063 research outputs found
Heavy Flavour Production at HERA
No full textMeasurements of open charm and beauty production at HERA provide important input for stringent tests of quantum chromodynamics and are used to constrain the parton distribution functions of the proton. The recent results on the heavy flavour production obtained by the H1 and ZEUS experiments at HERA are reviewed in this contribution
Structure Functions and PDF Determination at HERA
No full textAbstractIn 1992 the HERA collider provided the first collisions between 820 GeV protons and26.7 GeV electrons in the H1 and Zeus detectors. In this thesis the measurement of the F2(x, Q2 ) proton structure function is described, based on the H1 data which was taken in 1994. This data originated from collisions of 27.6 GeV positrons and 820 GeV protons, so that the totalsquared centre of mass energy was s = 4EeEp 10 5 GeV2 . The measurement covers the kinematic domain of squared momentum transfers Q2 between5 GeV2 and 100 GeV2 , and Bjorken x values between 10-4 and 10-2 , which could not be accessed by previous fixed target experiments.With an integrated luminosity of 2.5 pb- 1 which means a tenfold higher statistics than in 1993, the observation of a rise of F2 with decreasing x at a given Q2 is confirmed. Thegluon density is extracted from the scaling violations of F2 by means of an approximate solution of the QCD evolution equations and is found to rise steeply with decreasing x. This result is compatible with a recent QCD analysis of the data
Determination of Strange Quark Distribution Using Recent CMS Measurements on Production
No full textAssociated W+charm production in proton-proton collisions at the LHC probes the strange quark in the proton at leading order. Recent CMS measurements of associated W+charm production and W muon charge asymmetry at 7 TeV are used together with HERA DIS data in a QCD analysis at next-to-leading order. The HERAFitter framework is used. The strange-quark fraction is determined as a function of the scaling variable x. Results are compared to measurements of ATLAS and NOMAD experiments
HERA PDFs
No full textThe parton distribution functions (PDFs) of the proton are necessary non-perturbative inputs for calculating almost all scattering processes at hadron colliders. An overview of the HERA PDF sets determined by the H1 and ZEUS collaborations and an open source project for PDF determination, HERAFitter, are presented in this report
Measurement of Multijet Production in Collisions at High and Determination of the Strong Coupling s
No full textFirst Measurement of Charged Current Cross Sections with Longitudinally Polarised Positrons at HERA
No full textThe analysis presented in this thesis concerns the deep inelastic
charged current scattering cross sections measured with the H1 detector at HERA.
The analysed data were taken in the years 2003-04 at a centre-of-mass energy
and comprise two periods of
positron beams with positive and negative longitudinal polarisation, corresponding
to an integrated luminosity of 26.9 and 20.7 , respectively.
The cross sections are measured in a kinematic region of
four-momentum transfer squared and inelasticity
. \\
From the analysed data the polarisation dependence of the total charged current
cross section is determined for the first time at high . The results are
compared with predictions of the Standard Model and found to be in agreement,
i.e. possible contributions from non-standard right-handed currents are
consistent with zero
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