https://doi.org/10.1140/epja/i2004-10007-y
Nucleon-pole contributions in the 
, 
, 
and 
decays
1
Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918(4), 100039, Beijing, PRC
2
China Center of Advanced Science and Technology (World Laboratory), P.O. Box 8730, 100080, Beijing, PRC
3
Department of Physics, Guangxi Normal University, 541004, Guilin, PRC
4
Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, 730000, Lanzhou, PRC
5
Institut für Theoretische Physik, Universität Tübingen, Auf der Morgenstelle 14, D-72076, Tübingen, Germany
* e-mail: shenpn@mail.ihep.ac.cn
Nucleon-pole contributions in the 
, 
, 
and 
decays are re-studied. Different contributions due to PS-PS and PS-PV couplings in the 
-N interaction and the effects of 
form factors are investigated in the decay channel. It is found that when the ratio of |F0|/|F
M
| takes a small value, without considering the form factor, the difference between PS-PS and PS-PV couplings is negligible. However, when the form factor is included, this difference is greatly enlarged. The resultant decay widths are sensitive to the form factors. As a conclusion, the nucleon-pole contribution as a background to the decay width is important in the decay and must be considered. In the 
and 
decays, its contribution is smaller by 0.1% with respect to the data. In the 
decay, it provides a rather important contribution without considering form factors. But the contribution is suppressed greatly when adding the off-shell form factors. Comparing these results with data will help us to select a proper form factor for such kind of decay.
© Società Italiana di Fisica and Springer-Verlag, 2004
