Systematic studies of charmonium-, bottomonium-, and Bc-like tetraquark states

We study the mass splittings of Q(1)q(2)(!) over bar (3)(q) over bar (4)(Q=c, b, q=u, d, s) tetraquark states with chromomagnetic interactions between their quark components. Assuming that X(4140) is the lowest J(PC)= 1(++) cs (c) over bar(s) over bar tetraquark, we estimate the masses of the other tetraquark states. From the obtained masses and defined measure reflecting effective quark interactions, we find the following assignments for several exotic states: (1) both X(3860) and the newly observed Zc(4100) seem to be 0(++) cn (c) over bar(n) over bar tetraquarks; (2) Z(c)(4100) is probably a 1(+-) cn (c) over bar(n) over bar tetraquark; (3) Z(c)(3900), X(3940), and X(4160) are unlikely compact tetraquarks; (4) Zc(4020) is unlikely a compact tetraquark, but seems the hidden-charm correspondence of Z(b)(10650) with J(PC)= 1(+-); and (5) Z(c)(4250) can be a tetraquark candidate but the quantum numbers cannot be assigned at present. We hope further studies may check the predictions and assignments given here.