Aj. Buras et R. Fleischer, LIMITATIONS IN MEASURING THE ANGLE-BETA BY USING SU(3) RELATIONS FOR B-MESON DECAY AMPLITUDES, Physics letters. Section B, 341(3-4), 1995, pp. 379-385
Flavour SU(3) symmetry of strong interactions and certain dynamical as
sumptions have been used in a series of recent publications to extract
weak CKM phases from B-decays into {pi pi, pi K, K ($) over bar K} fi
nal states. We point out that irrespectively of SU(3)-breaking effects
the presence of QCD-penguin contributions with internal u- and c-quar
ks precludes a clean determination of the angle beta in the unitarity
triangle by using the branching ratios only. This difficulty can be ov
ercome by measuring in addition the ratio x(d)/x(s) of B-d(0) - ($) ov
er bar B-d(0) to B-s(0) - ($) over bar B-s(0) mixings. The measurement
of the angle gamma is unaffected by these new contributions. Some spe
cific uncertainties related to SU(3)-breaking effects and electroweak
penguin contributions are briefly discussed.