PENGUIN ZOOLOGY IN B-]PI-PI AND THE EXTRACTION OF THE CKM ANGLE-ALPHA

We reanalyze the decay B-d --> pi(+)pi(-) without assuming dominance o f QCD penguins with internal top-quark exchanges. In that case the wea k phase of the (b) over bar --> (d) over bar QCD penguin amplitude is not related in a simple way to the CKM angle beta. Nevertheless it is still possible to extract the CKM angle alpha in a transparent and alm ost model-independent way from the time-dependent CP-violating asymmet ry of the transition B-d --> pi(+)pi(-). Aside from that CP asymmetry this approach needs as an input only amplitudes of decays with branchi ng ratios of order 10(-5) and will thus be well within reach at future B-factories. (C) 1997 Elsevier Science B.V.