Berlin 2005 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 19: Theorie

HK 19.5: Vortrag

Montag, 7. März 2005, 15:30–15:45, TU MA005

Hadronic decays of η and η′ — •R. Nißler and B. Borasoy — Helmholtz-Institut für Strahlen- und Kernphysik (Theorie), Universität Bonn, Germany

Future experiments at the planned WASA at COSY facility [1] aim for a precision determination of η and η′ decay parameters and have stimulated renewed interest in accurate theoretical investigations of such processes. In this context, the isospin-breaking decays of η and η′ into three pions play a prominent role since electromagnetic effects are negligible and hence their decay amplitude is directly proportional to the light quark mass difference m_d − m_u. Furthermore, the hadronic decays of η and η′ provide important information on η-η′ mixing.

Employing a unitarized U(3) chiral effective field theory which includes final state interactions in the s- and p-wave amplitudes, we have calculated the decay widths and Dalitz plot parameters of the hadronic decays η → π π π, η′ → π π π and η′ → η π π extending previous work on s-waves [2]. We find p-wave interactions to be important in the decay η′ → π⁺ π⁻ π⁰, where phase space is large enough to allow for significant contributions of the ρ(770) resonance.

Financial support of the DFG is gratefully acknowledged.

• [1] B. Höistad et al., “Proposal for WASA at COSY”,
    http://www.fz-juelich.de/ikp/wasa/
• [2] N. Beisert and B. Borasoy, Nucl. Phys. A716 (2003) 186.