Freiburg 2008 – scientific programme

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T: Fachverband Teilchenphysik

T 13: Flavorphysik (Theorie) I

T 13.1: Talk

Wednesday, March 5, 2008, 16:45–17:00, KGI-HS 1132

B→ χ_cJ K decays revisited — Martin Beneke and •Leonardo Vernazza — Institut für Theoretische Physik E, RWTH Aachen

Recently, the hypothesis that exclusive B decays to charmonia H, such as B → H K, should factorize in the heavy quark limit and non-relativistic limit was not confirmed, when the formalism was applied to P-wave charmonium states, due to the appearance of infrared (IR) divergences. We show that factorization is recovered, if one includes the charmonium bound-state scales m_c v, m_c v² into the theoretical framework, and assume them to be intermediate between the heavy quark masses m_b, m_c and Λ_QCD. In this case the IR divergences problem is solved by the introduction of colour-octet operators, not considered before, but necessary for a consistent perturbative calculation of the decay amplitude at order α_s v (NLO). The appearance of endpoint singularities at leading twist in the spectator scattering contribution to the amplitude is solved in a similar way. We then provide estimates for the branching fractions.