Comparing B -> Xu l nul to B -> Xs gamma
Abstract
We suggest a method to determine Vub / Vts through a comparison of B -> Xu l nul and B -> Xs gamma. The relevant quantity is the spectrum of the light-cone component of the final state hadronic momentum, which in B -> Xs gamma is the photon energy while in B -> Xu l nul this requires a measurement of both hadronic energy and hadronic invariant mass. The non-perturbative contributions at tree level to these distributions are identical and may be cancelled by taking the ratio of the spectra. Radiative corrections to this comparison are discussed to order alphas and are combined with the non-perturbative contributions.
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