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Title: Measurement of the nucleon structure function F2 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 Q2 ranging from 0.2 to 5 GeV2. These data, together with previous measurements of the inclusive electron scattering off proton and deuteron, which cover a similar continuous two-dimensional region of Q2 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 F2 structure function and its moments. Using an OPE-based twist expansion, we studied the Q2-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 F2 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. Lastly, we speculate that the spatialmore » 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:
OSTI Identifier:
986373
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