784 research outputs found
Strange sea determination from collider data
We consider determinations of the strange sea in the nucleon based on the QCD
analyses of data collected at the LHC with focus on the recent high-statistics
ATLAS measurement of the - and -boson production. We study the effect
of different functional forms for parameterization of the parton distribution
functions and the combination of various data sets in the analysis. We compare
to earlier strange sea determinations and discuss ways to improve them in the
future.Comment: 13 pages, 7 figure
Fixed target Drell-Yan data and NNLO QCD fits of parton distribution functions
We discuss the influence of fixed target Drell-Yan data on the extraction of
parton distribution functions at next-to-next-to-leading order (NNLO) in QCD.
When used in a parton distribution fit, the Drell-Yan (DY) data constrain sea
quark distributions at large values of Bjorken x. We find that not all
available DY data are useful for improving the precision of parton distribution
functions (PDFs) obtained from a fit to the deep inelastic scattering (DIS)
data. In particular, some inconsistencies between DIS-based parton distribution
functions and DY data for large values of dilepton rapidity are found. However,
by selecting a sample of the DY data that is both representative and consistent
with the DIS data, we are able to perform a combined PDF fit that significantly
improves the precision of non-strange quark distributions at large values of x.
The NNLO QCD corrections to the DY process are crucial for improving the
precision. They reduce the uncertainty of the theoretical prediction, making it
comparable to the experimental uncertainty in DY cross-sections over a broad
range of x.Comment: 12 pages, revte
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