B<inf>d</inf>⁰(t) → π⁺ π^- and B<inf>s</inf>⁰(t) → K⁺ K^- decays: A tool to measure new-physics parameters

If physics beyond the standard model is present in B decays, experimental measurements seem to suggest that it principally affects those processes with significant b̄ → s̄ penguin amplitudes. It was recently argued that, in general, such new-physics (NP) effects can be parametrized in terms of a single NP amplitude Aq and phase Φq, for q = u, d, s, c. In this paper, we show that the study of the decays Bs0(t) → K+ K- and Bd0(t) → π+ π- allows one to measure the NP parameters Au and Φu. We examine the implications for this method of the latest experimental results on these decays. If NP is found in Bs0(t) → K+ K -, it can be partially identified through measurements of B s0(t) → K0 K̄0. © 2005 The American Physical Society.