On the origin of the narrow peak and the isospin symmetry breaking of the X(3872)

الأصل · EN

The X(3872) formation and decay processes in the B-decay are investigated by a c c-two-meson hybrid model. The two-meson state consists of the D⁰ D*⁰, D+D*⁻, J/ψρ, and J/ψω channels. The energy-dependent decay widths of the ρ and ω mesons are introduced. The D- D* interaction is taken to be consistent with a lack of the B B* bound state. The coupling between the D D* and J/ψρ or the D D* and J/ψω channels is obtained from a quark model. The c c-D D* coupling is taken as a parameter to fit the X(3872) mass. The spectrum is calculated up to 4 GeV. It is found that very narrow J/ψρ and J/ψω peaks appear around the D⁰ D*⁰ threshold. The size of the J/ψπ³ peak we calculated is 1.29-2.38 times as large as that of the J/ψπ². The isospin symmetry breaking in the present model comes from the mass difference of the charged and neutral D and D* mesons, which gives a sufficiently large isospin mixing to explain the experiments. It is also found that values of the ratios of the transfer strengths can give the information on the X(3872) mass or the size of the c c-D D* coupling.