One-pion exchange in the X(3872) revisited
  We re-examine one-pion exchange as a possible binding mechanism in the X(3872) charmonium-like state and argue it to be not sufficiently binding for this purpose. We conclude therefore that other short-range dynamics are responsible for the X formation. 
Yu. S. Kalashnikova, A. V. Nefediev (ITEP, Moscow)
hep-ph hep-ex nucl-th