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HK: Physik der Hadronen und Kerne

HK 29: Theorie V

HK 29.4: Talk

Wednesday, March 21, 2001, 15:30–15:45, B

Eta meson production in nucleon-nucleon collisions — •Vadim Baru¹, Johann Haidenbauer¹, Josef Speth¹, and Alexander Kudryavtsev² — ¹FZ Jülich, IKP, 52425 Jülich — ²ITEP, Moscow, Russia

We report on a microscopic calculation of near-threshold η-meson production in the reaction NN → NNη. We assume that the η meson is produced via elementary rescattering processes M N → η N of various mesons M = π, ρ, .... The corresponding amplitudes are taken from a coupled channel model of the π N system developed by the Jülich group [1]. This model contains explicitly the channels π N, ρ N, η N, π N^*(1520), σ N and π Δ. The interactions in and between the various channels are derived in the meson-exchange picture starting out from effective Lagrangians and are then iterated in a Lippmann-Schwinger type equation. Effects of the initial- and final state NN interaction are taken into account. Our results are compared with recent data from the COSY [2] and CELSIUS [3] accelerator facilities. 0.1cm

[1] O. Krehl et al., Phys. Rev. C 62, 02507 (2000)

[2] J. Smyrski et al., Phys. Lett. B 474, 182 (2000)

[3] H. Calén et al., Phys. Lett. B 366, 39 (1996); Phys. Rev. Lett. 79, 2642 (1997); Phys. Rev. C 58, 2667 (1998)