Search for $B^0\to X(3872)\gamma$

We report the results of a search for the decay $B^0 \to X(3872)(\to J/\psi \pi^+ \pi^-) \gamma$. The analysis is performed on a data sample corresponding to an integrated luminosity of $711{\mathrm{f}\mathrm{b}}^{-1}$ and containing $772 \times 10^6 B\bar{B}$ pairs, collected with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider running at the $\mathrm{{\rm Y}}(4S)$ resonance energy. We find no evidence for a signal and place an upper limit of $$\mathcal{B}$(B^0 \to X(3872)\gamma)\times $\mathcal{B}$(X(3872) \to J/\psi \pi^+ \pi^-) < 5.1 \times 10^{-7}$ at 90% confidence level.