Structure of f0(980) from a coupled channel
of S-wave scattering
M.P. Locher - V.E. Markushin - H.Q. Zheng
Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
Received: 6 May 1997 / Revised version: 26 September 1997 / Published online: 20 February 1998
A coupled channel model is used to study the nature of the f0(980) resonance. It is shown that the existence of two poles close to threshold, as found in many data fits and confirmed here, can be reconciled with the molecular origin of the f0(980). Due to a strong coupling between channels the number of the S-matrix poles close to the physical region in the physical case exceeds the number of bare states introduced in the model.