Double-heavy tetraquark states with heavy diquark-antiquark symmetry

We calculate the masses of the QQ (q) over bar(q) over bar (Q = c,b; q= u,d,s) tetraquark states with the aid of heavy diquark-antiquark symmetry (HDAS) and the chromomagnetic interaction (CMI) model. The masses of the highest-spin (J = 2) tetraquarks that have only the (QQ)(3) over bar (c)((q) over bar(q) over bar)(3c) color structure are related with those of conventional hadrons using HDAS. Thereafter, the masses of their partner states are determined with the mass splittings in the CMI model. Our numerical results reveal that (i) the lightest cc (n) over bar(n) over bar (n = u, d) is an I(J(P)) = 0(1(+)) state around 3929 MeV (53 MeV above the DD* threshold), and none of the double-charm tetraquarks are stable; (ii) the stable double-bottom tetraquarks are the lowest 0(1(+)) bb (n) over bar(n) over bar around 10488 MeV (approximate to 116 MeV below the (B) over bar(B) over bar * threshold) and the lowest 1/2(1(+)) bb (n) over bar(s) over bar around 10671 MeV (approximate to 20 MeV below the (B) over bar(B) over bar (s)*//(B) over bar (s)(B) over bar* threshold); and (iii) the two lowest bc (n) over bar(n) over bar tetraquarks, namely the lowest 0(0(+)) around 7167 MeV and the lowest 0(1(+) ) around 7223 MeV, are in the nearthreshold states. Moreover, we discuss the constraints on the masses of double-heavy hadrons. Specifically, for the lowest nonstrange tetraquarks, we obtain T-cc < 3965 MeV, T-bb < 10627 MeV, and T-bc < 7199 MeV.

Automated summary

In this study, the masses of QQ (q) over bar(q) over bar tetraquark states are calculated using the HDAS and CMI model. The results indicate that double-charm tetraquarks are unstable, while stable double-bottom tetraquarks have specific mass ranges.