The branching fraction calculations of B-c(+) - psi(2S)pi(+), B-c(+) - J/psi K+ and B-c(+) - J/psi D-s(+) decays relative to that of the B-c(+) - J/psi pi(+) mode

摘要

The weak decay of B-c(+) into psi(2S)pi(+), J/psi K+ and J/psi D-s(+) mesons, observed by LHCb collaboration for the first time, are calculated in the model which takes into account the "factorizable" contributions and "nonfactorizable" corrections. The decays of B-c(+) mesons into charmonia and light hadrons are expected to be well described by the factorization approximation. In the standard model, B-c(+) - psi(2S)pi(+), J/psi K+ decays occur through only the tree-level diagrams and so there are no CP violation in these channels. The decay B-c(+) - psi(2S)pi(+) is expected to proceed mainly via a (b) over bar - (u) over baru (d) over bar transition because the B-c(+) - J/psi pi(+) decay has identical final state and similar event topology, where it is chosen as the relative branching fraction channel. The ratio of branching fractions B(B-c(+) - J/psi K+)/B(B-c(+) - J/psi pi(+)) is of particular interest since the CKM matrix element is suppressed by a factor vertical bar V-us/V-ud vertical bar(2) similar to 0.05, in which the B-c(+) - J/psi K+ occur through (b) over bar - (c) over baru (s) over bar transition, but the dominant amplitude of the decay B-c(+) - J/psi pi(+) is a (b) over bar - (c) over baru (d) over bar transition. The decay B-c(+) - J/psi D-s(+) is examined by color-allowed, color suppressed spectator and weak annihilation diagrams. The weak annihilation topology, in contrast to decays of other beauty hadrons, is not suppressed and can contribute significantly to the decay amplitude. Because of the B-c(+) - psi(2S)pi(+), B-c(+) - J/psi K+ and B-c(+) - J/psi D-s(+) branching fractions are calculated relative to the B-c(+) - J/psi pi(+) decay, this decay mode is estimated separately, the ratio between them are 0.327 +/- 0.028, 0.074 +/- 0.0057 and 3.257 +/- 0.293, respectively, that are compatible with the experimental data.