Studies of Charmonium Production in e~+e~- Annihilation and B Decays at BABAR

摘要

In an e~+e~- B factory, charmonium states can be produced through different mechanisms, e.g. direct production in e~+e~- annihilation, double charmonium production, and in B-meson decays. Prompt production of J/ψ or ψ(2S) in association with a second charmonium states has been observed by both the BABAR and the Belle experiments. These processes provide an opportunity to study both perturbative and non perturbative effects in QCD and to search for new charmonium states recoiling against the reconstructed J/ψ or ψ(2S). Using the full BABAR data set collected at the γ(4S) resonance, we measure the absolute branching fractions of the two-body decays of B mesons (B → KX_c), where X_c is a charmonium state. For events in which a B is fully reconstructed, the charmonium spectrum can be observed in an unbiased way by looking at the distribution of the K momentum in the rest frame of the recoiling B. We present also Dalitz plot analysis for the decays of B mesons to D~-D~0K~+ and D~0D~0K~+, and we report about the observation of the D_(s1)~*(2700)~+ resonance in these two channels, and obtain measurements of the mass and width.