Existence of \sigma(600)/\kappa(900)-Particle and New Chiral Scalar Nonet ``Chiralons''

Abstract

The \sigma(600) and \kappa(900), observed in the phase shift analyses, satisfy rather well the mass and width relation predicted by the SU(3)LsM and the SU(3)LsM with the vector and axial-vector meson nonets, and deserve to be the members of scalar \sigma-nonet, together with the observed resonances a_0(980) and f_0(980), as a chiral partner of pseudoscalar \pi-nonet. In the phase shift analyses an introduction of repulsive background phase \delta_{BG} is essential, whose origin has a close connection to the \lambda\phi^4 interaction in LsM. It is argued that the members of this \sigma-nonet, "Chiralons", have different properties and should be discriminated from the conventional ^3P_0-qqbar-scalar nonet.