Köln 2004 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 11: Poster Session: Electromagnetic and Hadronic Probes
HK 11.11: Poster
Dienstag, 9. März 2004, 13:30–15:30, Foyer
Spin-dependence of Meson Production in Nucleon-Nucleon Collisions — •P. N. Deepak1, G. Ramachandran2, M. S. Vidya3, and C. Hanhart1 — 1Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich — 2Indian Institute of Astrophysics, Bangalore-560 034, India — 3School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110 067, India
The dynamics of the reaction NN→ NNπ, near threshold, is closely linked to NN scattering as it is the lowest inelastic channel in NN collisions. In this light, it is puzzling that although the NN interaction is believed to be well understood phenomenologically, there is currently no theoretical explanation for the wealth of polarization data available for NN→ NNπ. To find the missing physics, a partial-wave analysis of the data is mandatory.
To carry out this program, we employ a model-independent irreducible tensor approach to NN→ NNπ developed by Ramachandran et al., which leads to a spin-structure of the T-matrix valid at all energies together with exact partial-wave expansions for the reaction amplitudes. Further, in contrast to the earlier theoretical work of Bilenky and Ryndin, leading to expressions for the singlet and triplet total cross sections, channel-spin cross sections are defined at the differential level itself and their empirical determination from appropriate measurements using polarized beams and targets are indicated. Values for the singlet and triplet differential cross sections based on the recent data from IUCF are also presented here. The above formalism applies equally well to the production of pseudoscalar mesons like η, η′, presently of interest to COSY.