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HK: Physik der Hadronen und Kerne

HK 5: Theorie I

HK 5.4: Talk

Monday, March 17, 2003, 17:15–17:30, D

π⁺ absorption on ³He using modern trinucleon wavefunctions — •Sonja Schneider¹, Johann Haidenbauer¹, Christoph Hanhart¹, and Jouni A. Niskanen² — ¹Institut für Kernphysik, Forschungszentrum Jülich, 52425 Jülich — ²Department of Physical Sciences, University of Helsinki

We study quasifree π⁺ absorption on two nucleons in ³He employing a new parametrization of three–nucleon wave functions. The basic improvement lies in the use of a totally antisymmetric wave function and in the use of a nonseparable fit allowing for correlations between the nucleon–nucleon pair and the spectator momenta. Both points have an effect on the observables for π⁺ absorption on ³He, leading to a better description of the differential cross section and polarization data as compared to earlier calculations. However, there are hints that the polarization data in quasifree kinematics can not be described by two–body absorption mechanisms only.