2016/05/31 by V. Baru, E. Epelbaum, A. A. Filin +3 · 1 citation
Physics and Astronomy · #hep-ph
paper · pdf · doi:10.1016/j.physletb.2016.10.008
published as Phys. Lett. B763 (2016) 20 · 17 pages, 3 figures, 1 table, version published in Phys.Lett.B
arxiv created 2016/11/03 · arxiv updated 2016/11/04
We revisit the consequences of the heavy-quark spin symmetry for the possible spin partners of the X(3872). We confirm that, if the X(3872) were a DD^* molecular state with the quantum numbers JPC=1++, then in the strict heavy-quark limit there should exist three more hadronic molecules degenerate with the X(3872), with the quantum numbers 0++, 1+-, and 2++ in line with previous results reported in the literature. We demonstrate that this result is robust with respect to the inclusion of the one-pion exchange interaction between the D mesons. However, this is true only if all relevant partial waves as well as particle channels which are coupled via the pion-exchange potential are taken into account. Otherwise, the heavy-quark symmetry is destroyed even in the heavy-quark limit. Finally, we solve the coupled-channel problem in the 2++ channel with nonperturbative pions beyond the heavy-quark limit and, contrary to the findings of previous calculations with perturbative pions, find for the spin-2 partner of the X(3872) a significant shift of the mass as well as a width of the order of 50 MeV.