B → XcJ K decays revisited

We demonstrate that exclusive B decays to P-wave charmonium factorize in the non-relativistic limit provided that colour-octet contributions are taken into account, and estimate the branching fractions. Although there are very large uncertainties, we find reasonable parameter choices, where the main features of the data - large corrections to (naive) factorization and suppression of the X,2 and it, final states - are reproduced though the suppression Of Xc(2) is not as strong as seen in the data. Our results also provide an example, where an endpoint divergence in hard spectator-scattering factorizes and is absorbed into colour-octet operator matrix elements. (c) 2008 Elsevier B.V. All rights reserved.