X(3872)   by   Y.S. Kalashnikova,   Phys. Rev. D72, 034010 (2005)

bare cc state

coupled channel state

Spectral density ³P₁ state.
The 2³P₁ resonance shifts down to the DD^* threshold.
For the charmonium states Y.S. Kalashnikova considers:
One cc channel and six meson-meson channels:
DD, DD^*, D^*D^*, D_sD_s , D_sD_s^* and D_s^*D_s^*
The calculations are performed perturbatively to first order
in the harmonic oscillator approximation.
Confinement in the cc sector is achieved by using
the Cornell approximation of the Richardson potential.
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