Looking for new physics in Bd0-Bd0 mixing

There are variety of methods which directly test for the presence of new physics in the b→s flavor-changing neutral current (FCNC), but none which cleanly probe new physics in the b→d FCNC. One possible idea is to compare the weak phase of the t-quark contribution to the b→d penguin, which is -β in the SM, with that of Bd0-Bd0 mixing (-2β in the SM). In this talk I show that, in fact, it is impossible to measure the weak phase of the t-quark penguin, or indeed any penguin contribution, without theoretical input. However, if one makes a single assumption involving the hadronic parameters, it is possible to obtain the weak phase. I discuss how one can apply such an assumption to the time-dependent decays Bd0(t)→K0K0 and Bs0(t)→φKs in order to detect new physics in the b→d FCNC