Evidence of a New Narrow Resonance Decaying to χc1γ in B → χc1γK

We report measurements of B -> chi(c1)gamma K and chi(c2)gamma K decays using 772 x 10(6) B((B) over bar) events collected at the Y(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 +/- 1.8(stat) +/- 0.7(syst) Mev/c(2), a value that is consistent with theoretical expectations for the previously unseen 1(3)D(2) c((c) over bar) meson. We find no other narrow resonance and set upper limits on the branching fractions of the X(3872) -> chi(c1)gamma and chi(c2)gamma decays.