Mp. Locher et al., STRUCTURE OF F(0)(980) FROM A COUPLED-CHANNEL ANALYSIS OF S-WAVE PI-PI SCATTERING, EUROPEAN PHYSICAL JOURNAL C-PARTICLES AND FIELDS, 4(2), 1998, pp. 317-326
A coupled channel model is used to study the nature of the f(0)(980) r
esonance. It is shown that the existence of two poles close to <K(K)ov
er bar> threshold,as found in many data fits and confirmed here, can b
e reconciled with the <K(K)over bar> molecular origin of the f(0)(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 n
umber of bare states introduced in the model.