Speaker
Description
We search for a $B$ decay mode where one can find a peak for a $D \bar{D}$ bound state predicted in effective theories and in Lattice QCD calculations, which has also been claimed from some reactions that show an accumulated strength in $D \bar{D}$ production at threshold. We find a good candidate in the $B^{+} \rightarrow K^{+} \eta \eta$ reaction, by looking at the $\eta \eta$ mass distribution. The choice of $\eta \eta$ to see the peak is based on results of calculations that find the $\eta \eta$ among the light pseudoscalar channels with stronger coupling to the $D \bar{D}$ bound state. We find a neat peak around the predicted mass of that state in the $\eta \eta$ mass distribution, with an integrated branching ratio for $B^{+} \rightarrow K^{+}$( $D \bar{D}$, bound) ; ( $D \bar{D}$, bound) $\rightarrow \eta \eta$ of the order of $1.5 \times 10^{-4}$, a large number for hadronic $B$ decays, which should motivate its experimental search.
