D-s*(+)(2317) and D-s*(+)(2460): Tetraquarks bound by the t Hooft instanton-induced interaction?
We calculate the influence of the t Hooft interaction on the single-charm (C=1) tetraquark (cq (q) over bar (2)) mass spectrum and find that three SU(3)-flavor multiplets (3(A),6,(15) over bar) are significantly lowered, while the LT overline GT 3 LT /overline GT (S)-plet is lifted, as compared with their unperturbed masses. States with the D-s(+) quantum numbers appear in two of the three lowered multiplets. The lower of the two states drops below both of the Okubo-Zweig-Iizuka (OZI)-allowed decay thresholds, thus being identified with D-s(*+)(2320), while the heavier state drops below the eta+D-s(+) threshold, but stays above the K+D one. A signature prediction of this theory is the lowering of the exotic tetraquark 6-plet and (15) over bar -plet: most of these states cannot consist of only one quark and one antiquark. As a test we suggest a search for two quasistable exotic tetraquarks with open-charm and strangeness: the (isotriplet) cs (q) over bar(q) over bar and the (isodoublet)... cq (s) over bar(s) over bar.