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

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.