Mechanism for a next-to-lowest lying scalar meson nonet

Abstract

Recent work suggests the existence of a non-conventional lowest-lying scalar nonet containing the a0(980). Then the a0(1450) and also the K0*(1430) are likely candidates to belong to a conventional p-wave $q\bar{q}$ nonet. However a comparison of their properties with those expected on this basis reveals a number of puzzling features. It is pointed out that these puzzles can be resolved in a natural and robust way by assuming a ``bare'' conventional p-wave scalar $q\bar{q}$ nonet to mix with a lighter four quark $qq\bar{q}\bar{q}$ scalar nonet to form new ``physical'' states. The essential mechanism is driven by the fact that the isospinor is lighter than the isovector in the unmixed $qq\bar{q}\bar{q}$ multiplet.

Comments: 22 pages, 6 figures