Bochum 2009 – wissenschaftliches Programm

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HK: Fachverband Hadronen und Kerne

HK 36: Nuclear Structure and Dynamics I

HK 36.9: Vortrag

Dienstag, 17. März 2009, 18:30–18:45, H-ZO 40

Color transparency and short-range correlations in exclusive pion and nucleon removal reactions from nuclei — •Wim Cosyn — Ghent University, Ghent, Belgium

A relativistic and quantum mechanical framework to compute nuclear transparencies for pion and nucleon production reactions is presented [1-3]. Final-state interactions for the ejected pions and nucleons are implemented in a relativistic Glauber eikonal approach. The proposed model can account for the color-transparency (CT) phenomenon and short-range correlations (SRC) in the nucleus. Results are presented for kinematics corresponding to completed experiments for A(γ,π⁺ n) and A(e,e′π⁻), A(p,2p) and A(e,e′p). The influence of CT and SRC on the nuclear transparency is studied. Both the SRC and CT mechanisms increase the nuclear transparency. The two mechanisms can be clearly separated, though, as they exhibit a completely different dependence on the hard-scale parameter. Recent A(e,e′π⁺) results [4] point towards the early onset of the CT phenomenon in pion production processes. The similarities in the trends and magnitudes of the computed nuclear transparencies compared to semi-classical models indicate that they are not subject to strong model dependences.

[1] W. Cosyn, M. C. Martínez, J. Ryckebusch, and B. Van Overmeire, Phys. Rev. C74, 062201(R) (2006) [2] W. Cosyn, M. C. Martínez, and J. Ryckebusch, Phys. Rev. C77, 034602 (2008) [3] B. Van Overmeire, W. Cosyn, P. Lava and J. Ryckebusch, Pys. Rev. C73, 064603 (2006) [4] B. Clasie et al. Phys. Rev. Lett. 99, 242502 (2007).