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Precision measurements of the F 2 structure function at large x in the resonance region and beyond. E12-10-002 , Spokespersons: S. Malace , I. Niculescu , C. Keppel. Distribution of quarks and gluons ( PDF s) inside the nucleon: fundamental characterization of its structure in QCD.
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Precision measurements of the F2 structure function at large x in the resonance region and beyond E12-10-002, Spokespersons: S. Malace, I. Niculescu, C. Keppel • Distribution of quarks and gluons (PDFs) inside the nucleon: fundamental characterization of its structure in QCD • Data scarce or with large uncertainties at large x • constrain PDFsat large x Need precision data on F2p(d) at large x to: New Milestone HP14 by 2018 • extend studies of local quark-hadron duality in F2(push PDFsextractionto x > 0.8) • Theory groups (CTEQ6X, Alekhinet al.) actively pursuing PDFs extraction at large x
E12-10-002: kinematics and projected accuracy Uncertainties(13 days beam time) E12-10-002: straightforward extension of the 6 GeV run E00-116 W2 > 4 GeV2 Q2: (4,17) • Statistical: 2% (dW2 = 0.1 GeV2), • 10 cm target and a 40 mAand 11 GeV beam x: (0.3,0.99) W2: < 9 significant improvement for W2 < 4 GeV2 over existing measurements from SLAC Systematicsfrom E00-116 exceeding 1% • Systematic: similar precision expected as for E00-116 QuantityUncertainty Charge-symmetric background < 2% Model dependence 0.2% - 5% Radiative corrections 0.5% - 3.6% • E12-10-002: expect reduction (background measured at same kinematics with same spectrometer) • E00-116: within 1% for W2 > 2 GeV2 • E12-10-002: determine R -> data at • another beam energy, 6.6 GeV R-uncertainty 2 %
E12-10-002: new developments since approval • CTEQ6X: used E00-116 (W2 > 3 GeV2) to constrain PDFs at large x : will use E12-10-002 (W2 > 3 GeV2) : can usequark-hadron duality (W2 > 1.9 GeV2) to push to x > 0.8 • HiX2010, Oct. 13 – 15 2010, Jefferson Lab http://conferences.jlab.org/HiX2010/ LOC: S. Malace (chair), R. Ent, W. Melnitchouk, I. Niculescu Topics: PDFs @ large x, quark-hadron duality & higher twists, lattice QCD etc.