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Precision Model Independent Determination of | V ub | from B → π l ν

2005; American Physical Society; Volume: 95; Issue: 7 Linguagem: Inglês

10.1103/physrevlett.95.071802

1092-0145

Christian M. Arnesen, Benjamı́n Grinstein, Ira Z. Rothstein, Iain W. Stewart,

Black Holes and Theoretical Physics

A precision method for determining |Vub| using the full range in q^2 of B-> pi \ell nu data is presented. At large q^2 the form factor is taken from unquenched lattice QCD, at q^2=0 we impose a model independent constraint obtained from B-> pi pi using the soft-collinear effective theory, and the shape is constrained using QCD dispersion relations. We find |Vub| =(3.54\pm 0.17\pm 0.44) x 10^{-3}. With 5% experimental error and 12% theory error, this is competitive with inclusive methods. Theory error is dominated by the input points, with negligible uncertainty from the dispersion relations.