The Effects of Charged Charm Mesons on the Line Shapes of the X(3872)

Understand

The quantum numbers J^PC = 1++ of the X(3872) and the proximity of its mass to the D*0 anti-D0 threshold imply that it is either a loosely-bound hadronic molecule whose constituents are a superposition of D*0 anti-D0 and D0 anti-D*0 or it is a virtual state of charm mesons.

• The line shapes of the X(3872) can discriminate between these two possibilities.
• At energies within a few MeV of the D*0 anti-D0 threshold, the lines shapes of the X produced in B -> K transitions are determined by its binding energy and its width.
• Their normalizations are determined by a short-distance constant that is different for B+ -> K+ and B0 -> K0.