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Title: Measurement of the nucleon structure function F 2 in the nuclear medium and evaluation of its moments

We report on the measurement of inclusive electron scattering off a carbon target performed with CLAS at Jefferson Laboratory. A combination of three different beam energies 1.161, 2.261 and 4.461 GeV allowed us to reach an invariant mass of the final-state hadronic system W ≈ 2.4 GeV with four-momentum transfers Q 2 ranging from 0.2 to 5 GeV 2. These data, together with previous measurements of the inclusive electron scattering off proton and deuteron, which cover a similar continuous two-dimensional region of Q 2 and Bjorken variable x, permit the study of nuclear modifications of the nucleon structure. By using these, as well as other world data, we evaluated the F 2 structure function and its moments. Using an OPE-based twist expansion, we studied the Q 2-evolution of the moments, obtaining a separation of the leading-twist and the total higher-twist terms. The carbon-to-deuteron ratio of the leading-twist contributions to the F 2 moments exhibits the well known EMC effect, compatible with that discovered previously in x-space. The total higher-twist term in the carbon nucleus appears, although with large systematic uncertainites, to be smaller with respect to the deuteron case for n < 7, suggesting partial parton deconfinement in nuclear matter.more » Lastly, we speculate that the spatial extension of the nucleon is changed when it is immersed in the nuclear medium.« less
Authors:
 [1]
  1. INFN, Genova (Italy); Skobeltsyn Nuclear Physics Institute, Moscow (Russia). et al.
Publication Date:
Report Number(s):
JLAB-PHY-10-1132; DOE/OR/23177-1160; arXiv:1002.3776
Journal ID: ISSN 0375-9474; TRN: US1006338
Grant/Contract Number:
AC05-06OR23177
Type:
Accepted Manuscript
Journal Name:
Nuclear Physics. A
Additional Journal Information:
Journal Volume: 845; Journal Issue: 1-4; Journal ID: ISSN 0375-9474
Publisher:
Elsevier
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; CARBON; CEBAF ACCELERATOR; DEUTERONS; ELECTRONS; EMC EFFECT; EVALUATION; FOUR MOMENTUM TRANSFER; MODIFICATIONS; NUCLEAR MATTER; NUCLEONS; PROTONS; SCATTERING; STRUCTURE FUNCTIONS; TARGETS; moments; nuclear modifications; nucleon structure; higher twists; QCD; OPE
OSTI Identifier:
986373