2005/08/31 by Hai-Yang Cheng, Chun-Khiang Chua, Kwei-Chou Yang · 1 citation
Physics and Astronomy · #hep-ph #hep-ex
paper · pdf · doi:10.1103/physrevd.73.014017
published as Phys.Rev.D73:014017,2006 · 42 pages and 5 figures. Form factors for B to excited scalar mesons are calculated, signs are flipped for the decay constants of excited states (Appendix B), Tables 5 to 9 are revised. Version to appear in PRD
arxiv created 2005/12/01 · arxiv updated 2009/12/01
The hadronic charmless B decays into a scalar meson and a pseudoscalar meson are studied within the framework of QCD factorization. Although the light scalar mesons f0(980) and a0(980) are widely perceived as primarily the four-quark bound states, in practice it is difficult to make quantitative predictions based on the four-quark picture for light scalars. Hence, predictions are made in the 2-quark model for the scalar mesons. Based on the QCD sum rule method, we have derived the leading-twist light-cone distribution amplitudes of scalar mesons and their decay constants. The short-distance approach suffices to explain the observed large rates of f0(980)K- and f0(980) K0 that receive major penguin contributions from the b→ ss s process. When f0(980) is assigned as a four-quark bound state, there exist extra diagrams contributing to B→ f0(980)K. Therefore, a priori the f0(980)K rate is not necessarily suppressed for a four-quark state f0(980). The calculated B0→ a0+(980)π- and a0+(980)K- rates exceed slightly the current experimental limits. If the branching ratio of B0→ a0+(1450)π- is measured at the level of (4∼ 6)× 10-6 while a0+(980)π- is found to be smaller, say, of order (1∼ 2)× 10-6 or even smaller than this, it will be likely to imply a 2-quark nature for a0(1450) and a four-quark assignment for a0(980). The penguin-dominated modes a0(980)K and a0(1450)K receive dominant weak annihilation contributions.