The a0(980), a0(1450) and K0∗(1430) scalar decay constants and the isovector scalar spectrum

The scalar correlator Π(q2)=i∫d4x eiq·x〈0|TJ(x)J†(0)|0〉 (with J=∂μd̄γμu) is studied using a class of finite energy sum rules shown recently to be very well satisfied in the vector isovector channel. The values of the a0 scalar decay constants extracted in this analysis, which describe the couplings of the a0(980) and a0(1450) to the current J, are shown to be comparable, strongly disfavoring any scenario in which the a0(980) is interpreted as a loosely bound KK̄ molecule and the a0(1450) is assigned to the same flavor multiplet as the K0∗(1430). The a0 decay constants are also compared to the analogous decay constant describing the coupling of the K0∗(1430) to the divergence of the strange vector current, Js=∂μs̄γμu (which may be obtained from experimental Ke3 and Kπ phase shift data) and implications of the relative magnitudes for the interpretation of the nature of the a0 states discussed.