Investigation of the possible DD*/BB* and DD*/BB* bound states

In this work, we systematically study the D (D) over bar*=B (B) over bar* and D (D) over bar*=B (B) over bar* systems with the Bethe-Salpeter equation in the ladder and instantaneous approximations for the kernel. By solving the Bethe-Salpeter equation numerically with the kernel containing the direct and crossed one-particle exchange diagrams and introducing three different form factors (monopole, dipole, and exponential form factors) at the vertices, we find only the isoscalar D (D) over bar*=B (B) over bar* and DD (D) over bar*= B (B) over bar* systems can exist as bound states. This indicate that the X(3872) and T+cc could be accommodated as IG(JPC) = 0+(1++) D (D) over bar* and (I)JP = (0)1+ D (D) over bar* bound states while the bound-state explanations for Zb(10610) and Zc(3900) are excluded.

Automated summary

The study shows that only the isoscalar D (D) over bar*=B (B) over bar* and DD (D) over bar*= B (B) over bar* systems can exist as bound states, while other systems do not meet this criterion.