New Predictions for Multiquark Hadron Masses

The recent reported charmed-strange resonance at 2.32 GeV/c suggests a possible multiquark state. Three types of multiquark bound states are reviewed. A previous model-independent variational approach considers a tetraquark with two heavy antiquarks and two light quarks as a heavy antidiquark with the color field of a quark bound to the two light quarks with a wave function like that of a heavy baryon. Results indicate that a charmed-strange tetraquark $\bar c \bar s u d$orabottom-strangetetraquark$\bar b \bar s u d$ with this “diquark-heavy-baryion” wave function is not bound, in contrast to “molecular-type” $D-K$ and $B-K$ wave functions. However, a charmed-bottom tetraquark $\bar{c}\bar{b}ud$ might be bound with a very narrow weak decay mode. A “molecular-type” $D-B$ state can have an interesting $B_c\pi$ decay with a high energy pion,