Spin-Dependent Structure Functions in Nuclear Matter and the Polarized EMC Effect

Journal Article · Fri Jul 29 04:00:00 EDT 2005 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.95.052302· OSTI ID:20699254

Cloeet, I C ^[1]; Bentz, W ^[2]; Thomas, A W ^[3]

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1. Special Research Centre for the Subatomic Structure of Matter and Department of Physics and Mathematical Physics, University of Adelaide, South Australia 5005 (Australia)
2. Department of Physics, School of Science, Tokai University, Hiratsuka-shi, Kanagawa 259-1292 (Japan)
3. Jefferson Lab, 12000 Jefferson Avenue, Newport News, Virginia 23606 (United States)

An excellent description of both spin-independent and spin-dependent quark distributions and structure functions has been obtained with a modified Nambu-Jona-Lasinio model, which is free of unphysical thresholds for nucleon decay into quarks--hence incorporating an important aspect of confinement. We utilize this model to investigate nuclear medium modifications to structure functions and find that we are readily able to reproduce both nuclear matter saturation and the experimental F{sub 2N}{sup A}/F{sub 2N} ratio, that is, the European Muon Collaboration (EMC) effect. Applying this framework to determine g{sub 1p}{sup A}, we find that the ratio g{sub 1p}{sup A}/g{sub 1p} differs significantly from unity, with the quenching caused by the nuclear medium being about twice that of the spin-independent case. This represents an exciting result, which, if confirmed experimentally, will reveal much about the quark structure of nuclear matter.

• OSTI ID: 20699254
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 5 Vol. 95; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
COLOR MODEL
EMC EFFECT
HADRONIC PARTICLE DECAY
NUCLEAR MATTER
NUCLEONS
QUARKS
SPIN
STRUCTURE FUNCTIONS