Quark mass dependence of the X(3872) binding energy

We explore the quark-mass dependence of the pole position of the X(3872) state within the molecular picture. The calculations are performed within the framework of a nonrelativistic Faddeev-type three-body equation for the DD¯π system in the JPC=1++ channel. The πD interaction is parametrised via a D⁎ pole, and a three-body force is included to render the equations well defined. Its strength is adjusted such that the X(3872) appears as a DD¯⁎ bound state 0.5 MeV below the neutral threshold. We find that the trajectory of the X(3872) depends strongly on the assumed quark-mass dependence of the short-range interactions which can be determined in future lattice QCD calculations. At the same time we are able to provide nontrivial information on the chiral extrapolation in the X channel.