Evidence of a new narrow resonance decaying to $chi_{c1}gamma$ in $B to chi_{c1} gamma K$

We report measurements of $B to chi_{c1} gamma K$ and $chi_{c2} gamma K$ decays using $772 times 10^{6}$ $Bbar{B}$ events collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. Evidence of a new resonance in the $chi_{c1} gamma$ final state is found with a statistical significance of $3.8 sigma$. This state has a mass of $3823.1 pm 1.8 {(stat)} pm 0.7 {(syst)}$ MeV/$c^2$, a value that is consistent with theoretical expectations for the previously unseen $1^3 D_2$ $cbar{c}$ meson. We find no other narrow resonance and set upper limits on the branching fractions of the $X(3872) to chi_{c1} gamma$ and $chi_{c2} gamma$ decays.