Constraining the CKM parameters usingCPviolation in semileptonicBdecays

Abstract

We discuss the usefulness of the $\mathrm{CP}$ violating semileptonic asymmetry $a_{\mathrm{SL}}$ not only as a signal of new physics, but also as a tool in constraining the Cabibbo-Kobayashi-Maskawa parameters. We show that this technique could yield useful results in the first years of running at the B factories. We present the analysis graphically in terms of $M_{12},$ the dispersive part of the $B^0$-$B^0$ mixing amplitude. This is complementary to the usual unitarity triangle representation and often allows a cleaner interpretation of the data.