Analysis of the γγ→DD¯ reaction and the DD¯ bound state

2021

In this work, we investigate the reaction of $\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}D\overline{D}$, taking into account the $S$-wave $D\overline{D}$ final state interaction. By fitting to the $D\overline{D}$ invariant mass distributions measured by the Belle and BABAR Collaborations, we obtain a good reproduction of the data by means of a $D\overline{D}$ amplitude that produces a bound $D\overline{D}$ state with isospin $I=0$ close to threshold. The error bands of the fits indicate, however, that more precise data on this reaction are needed to be more assertive about the position and width of such a state.