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HK: Physik der Hadronen und Kerne

HK 14: Postersitzung / Theorie

HK 14.22: Poster

Donnerstag, 23. März 2000, 10:15–12:45, B 113

Coherence length effects in diffractive ρ-electroproduction on nuclei — •Thorsten Renk, Gunther Piller, and Wolfram Weise — Technische Universität München

Vector meson electroproduction at low photon virtuality can be described using a hadronic picture which relates the production cross sections at the nucleon to the vector meson-nucleon scattering cross sections, whereas at high virtuality perturbative QCD (pQCD) provides a description in terms of partonic degrees of freedom. By probing the smooth transition between these two regions one hopes to investigate details of the vector meson formation out of initially produced partons. Embedding this process into a nucleus offers the opportunity to observe the detailed space-time evolution of the reaction via the re-scattering contributions. Another importent aspect is the role of the coherence length of the produced hadronic state. We present a calculation within the vector meson dominance model, using the hadronic degrees of freedom, which accounts for coherence length effects and compare to the ¹⁴N data published by the HERMES collaboration. Finally we discuss the possibility to see the onset of pQCD at HERMES.

(supported in part by BMBF)