| 摘要: |
The chiral symmetry of QCD requires energy-dependent pionic strong interactions at low energies. This constraint, however, is not fulfilled by the usual Breit-Wigner parametrization of pionic resonances, leading to masses larger than the real ones. We derive relations between nonleptonic three-body decays of the B meson into a D meson and a pair of light pseudoscalar mesons based on SU(3) chiral symmetry. Employing effective field theory methods, we demonstrate that taking into account the final-state interactions, the experimental data of the decays B--> D+pi(-)pi(-), B-s(0)-> (D) over bar (0) K-pi(+), B-0 -> (D) over bar (0)pi(-)pi(+), B- -> D+pi K--(-) and B-0 -> (D ) over bar (0)pi K--(+) can all be described by the nonperturbative pi/eta/K-D/D-s scattering amplitudes previously obtained from a combination of chiral effective field theory and lattice QCD calculations. The results provide strong support of the scenario that the broad scalar charmed meson D-0*(2400) should be replaced by two states, the lower one of which has a mass of around 2.1 GeV, much smaller than that extracted from experimental data using a Breit-Wigner parametrization. |
