Remarks on study of X(3872) from effective field theory with pion-exchange interaction.

In a recent paper [P. Wang and X.-G. Wang, Phys. Rev. Lett. 111, 042002 (2013)], the charmonium state X(3872) is studied in the framework of an effective field theory. In that work it is claimed that (i) the one-pion exchange (OPE) alone provides sufficient binding to produce the X as a shallow bound state at the D0D*0 threshold, (ii) short-range dynamics (described by a contact interaction) provides only moderate corrections to the OPE, and (iii) the X-pole disappears as the pion mass is increased slightly and therefore the X should not be seen on the lattice, away from the pion physical mass point, if it were a molecular state. In this paper we demonstrate that the results of P. Wang and X.-G. Wang suffer from technical as well as conceptual problems and therefore do not support the conclusions drawn by the authors. [ABSTRACT FROM AUTHOR]