Scalar mesons in a relativistic quark model with instanton-induced forces

In a relativistic quark model with linear confinement and an instanton-induced interaction which solves the η-η′ puzzle, scalar mesons are found as almost pure SU(3) flavor states. This suggests a new interpretation of the scalar nonet: We propose that the recently discovered ƒ0(1500) is not a glueball but the scalar (mainly) -octet meson for which the KK decay mode is suppressed. The mainly-singlet state is tentatively identified with the ƒ0(980). The isovector and isodoublet states correspond to the a0(1450) and K0∗(1430), respectively.