Medium modifications of the bound nucleon generalized parton distributions and the quark contribution to the spin sum rule
- Theory Center, Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)
- Excited Baryon Analysis Center (EBAC) and Theory Center, Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)
We estimate the nuclear medium modifications of the quark contribution to the bound nucleon spin sum rule, J{sup q}*, as well the separate helicity, {delta}{sigma}*, and the angular momentum, L{sup q}*, contributions to J{sup q}*. For the calculation of the bound nucleon generalized parton distributions (GPDs), we use as input the bound nucleon elastic form factors predicted in the quark-meson coupling model. Our model for the bound nucleon GPDs is relevant for incoherent deeply virtual Compton scattering (DVCS) with nuclear targets. We find that the medium modifications increase J{sup q}* and L{sup q}* and decrease {delta}{sigma}* compared to the free nucleon case. The effect is large and increases with increasing nuclear density {rho}. For instance, at {rho}={rho}{sub 0}=0.15 fm{sup -3},J{sup q}* increases by 7%, L{sup q}* increases by 20%, and {delta}{sigma}* decreases by 17%. These in-medium modifications of the bound nucleon spin properties are a general feature of relativistic mean-field quark models and may be understood qualitatively in terms of the enhancement of the lower component of the quark Dirac spinor in the nuclear medium.
- OSTI ID:
- 21286979
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 79, Issue 5; Other Information: DOI: 10.1103/PhysRevC.79.055205; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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