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HK: Physik der Hadronen und Kerne

HK 19: Theorie

HK 19.6: Vortrag

Montag, 7. März 2005, 15:45–16:00, TU MA005

Study of axial charge of N(1535) in threshold ηπ production — •Daisuke Jido¹, Atsushi Hosaka², and Makoto Oka³ — ¹Phyisik-Department, Technische Universität München,James-Franck-Strasse, D-85747 Garching — ²Research Center for Nuclear Physics, Osaka University, Ibaraki,Osaka, 567-0047, Japan — ³Physics Department, Tokyo Institute of Technology, Meguro, Tokyo, 152-8551, Japan

Axial charge is one of the most important static properties of hadrons. Especially a relatively negative sign of a parity partner of nucleon opens a new possibility to form a chiral doublet of nucleon and its parity partner. In the linear realization of chiral symmetry in nucleons, there are two possible ways to assign the chiral multiplets to nucleon and its parity partner depending on the sign of the axial charge of the parity partner. These two assignments are shown to have phenomenologically distinguished predictions. We report on a theoretical study of double meson production reaction of the eta and pi mesons in the threshold region in order to determine the sign of the axial charge of N(1535) (N^*). The eta meson is used as a probe for N^* production in the intermediate state. The pion emmited in the final state is then used to extract the sign of the axial charge. Calculating cross section of the π⁻p → π⁻η p reaction, we find that the most distinct dependence on the sign of N^* is seen in the slope of the angular distribution of the final π⁻ state as a result of an interference of the p-wave nature of the π N^*N^* coupling and the s-wave nature of the π NN^* coupling.
[1] D. Jido, M. Oka and A. Hosaka, Prog. Theor. Phys. 106 (2001) 823, 873.
^*Work of D.J. in Germany is supported by AvH.