Z(4430) and a new paradigm for spin interactions in tetraquarks

Following the recent confirmation of the Z+(4430) resonance with J(PG) = 1(++), we have re-examined the model of S- and P-wave tetraquarks. We propose a type-II diquark-antidiquark model which shows to be very effective at producing a simple and comprehensive picture of the J(PG) = 1(++) and 1(--) sectors of the recently discovered charged tetraquarks and of the observed Y resonances. The model is still faced with the unresolved difficulty of explaining why some states seem to have incomplete isospin multiplets.