Unitarity Triangle Without Semileptonic Decays
Abstract
Use of semi-leptonic decays has become standard in constraining the Unitarity Triangle. Bearing in mind that precise calculations of these are very challenging, we propose an entirely new approach. In particular the |Vcb| + epsilonK constraint, which depends extremely sensitively on Vcb in the traditional method, is replaced by the interplay between epsilonK, BR(B ->tau nu) and Delta MBs. It is found that even in this method tensions with the Standard Model persist at the ~1.8 sigma level. Furthermore, improvements on the B -> tau nu branching ratio and on the lattice determination of fBs Bs(1/2) can increase the effectiveness of this method significantly.
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