Is the Jᵖ=2- assignment for the X(3872) compatible with the radiative transition data?

الأصل · EN

The very recent analysis by BaBar Collaboration indicates that the X(3872) may favor the quantum number JPC=2⁻⁺ rather than the previously assumed 1⁺⁺. By pretending the ηc₂(1D) charmonium to be the X(3872), we study the parity-even radiative transition processes ηc₂(1D)→ J/ψ(ψ')+γ within several phenomenological potential models. We take the ³D₁ admixture in ψ' into account, and consider the contributions from the magnetic dipole (M1), electric quadrupole (E2), and magnetic octupole (M3) amplitudes. It is found that the ratio of the branching fractions of these two channels, as well as the absolute branching fraction of ηc₂→ ψ'γ, are in stark contradiction with the existing BaBar measurements. This may indicate that the 2⁻⁺ assignment for the X(3872) is highly problematic.