New, efficient and clean strategies to explore CP violation through neutral B decays

We point out that decays of the kind B-d --> D +/- K-S(L) and B-s --> D +/- eta('), D +/- phi,..., where D+ and D- denote the CP-even and CP-odd eigenstates of the neutral D-meson system, respectively, provide very efficient, theoretically clean determinations of the angle gamma of the unitarity triangle. In this new strategy, we use the B-q(0)-<(B-q(0))over bar> (q is an element of {d, s}) mixing phase phi(q) as an input, and employ only "untagged" and mixing-induced CP-violating observables, which satisfy a very simple relation, allowing us to determine tan gamma. Using a plausible dynamical assumption, gamma can be fixed in an essentially unambiguous manner. The corresponding formalism can also be applied to B-d --> D +/- pi(0), D +/- rho(0),... and B-s --> D +/- K-S(L) decays. Although these modes appear less attractive for the extraction of gamma, they provide interesting determinations of sin phi(q). In comparison with the conventional Bd --> J/psi K-S(L) and B-S --> J/psiphi methods, these extractions do not suffer from any penguin uncertainties, and are theoretically cleaner by one order of magnitude. (C) 2003 Published by Elsevier Science B.V.