Measuring new-physics parameters in B penguin decays

We examine new-physics (NP) effects in B decays with large (b) over bar --> (s) over bar penguin amplitudes. Decays involving (b) over bar --> (s) over bar penguins are assumed to be unaffected. We consider a model-independent parametrization of such NP. We argue that NP strong phases are negligible relative to those of the standard model. This allows us to describe the NP effects in terms of a small number of effective amplitudes A(q)(NP) (q = u, d, s, c) and corresponding weak phases Phi(q). We then consider pairs of neutral B decays which are related by flavour SU(3) in the standard model. One receives a large (b) over bar --> (s) over bar 9 penguin component and has a NP contribution; the other has a (b) over bar --> (d) over bar penguin amplitude and is unaffected by NP. The time-dependent measurement of these two decays allows the measurement of the NP parameters A(q)(NP) and Phi(q). The knowledge of these parameters allows us to rule out many NP models and thus partially identify the new physics. (C) 2004 Elsevier B.V. All rights reserved.