Measuring [V-td/V-ub] (=sin gamma/sin beta within the SM) through B -> M nu(nu)over-bar (M=pi, K,rho, K*) decays

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1998-07-01
We propose a new method for the precise determination of [V-td/V-ub] from the ratios of branching ratios B(B-->rho nu(nu)over-bar)/B(B-->rho iota nu) and B(B-->pi nu(nu)over-bar)/B(B-->pi l nu). These ratios depend only on the ratio of the Cabibbo-Kobayashi-Maskawa (CKM) elements [V-td/V-ub] with little theoretical uncertainty, when very small isospin breaking effects are neglected. As is well known, [V-td/V-ub] equals (sin gamma/sin beta) for the CKM version of CP violation within the standard model. We also give in detail analytical and numerical results on the differential decay width d Gamma(B-->K*nu(nu)over-bar)/dq(2) and the ratio of the differential rates dB(B-->rho nu(nu)over-bar)/dq(2)/dB(B-->K*nu(nu)over-bar)/dq(2) as well as B(B-->rho nu(nu)over-bar)/B(B-->K*nu(nu)over-bar) and B(B-->pi nu(nu)over-bar)/B(B-->K nu(nu)over-bar). [S0556-2821(98)00513-X].