2005/06/30 by C. Albertus, J. M. Flynn, E. Hernández +3 · 1 citation
Physics and Astronomy · #Neutrino Physics Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevd.72.033002
published as Phys.Rev. D72 (2005) 033002 · 17 pages, minor modifications. Accepted in PRD
arxiv created 2005/07/14 · openalex publication_date 2005/08/02 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
The semileptonic B\ensuremath→\ensuremathπl+\ensuremathνl decay is studied starting from a simple quark model which includes the influence of the B* pole. To extend the predictions of a nonrelativistic constituent quark model from its region of applicability near qmax2=(mB\ensuremath-m_\ensuremathπ)2 to all q2 values accessible in the physical decay, we use a novel multiply subtracted Omn\`es dispersion relation, which considerably diminishes the form-factor dependence on the elastic \ensuremathπB\ensuremath→\ensuremathπB scattering amplitudes at high energies. By comparison to the experimental branching fraction we extract |Vub|=0.0034\ifmmode±\else\textpm\fi0.0003(exp)\ifmmode±\else\textpm\fi0.0007(theory). To further test our framework, we also study D\ensuremath→\ensuremathπ and D\ensuremath→K decays and find excellent results f_\ensuremathπ+(0)/fK+(0)=0.80\ifmmode±\else\textpm\fi0.03, B(D0\ensuremath→\ensuremathπ^\ensuremath-e+\ensuremathνe)/B(D0\ensuremath→K^\ensuremath-e+\ensuremathνe)=0.079\ifmmode±\else\textpm\fi0.008. In particular for the D\ensuremath→\ensuremathπ case, we reproduce, with high accuracy, the three-flavor lattice QCD results recently obtained by the Fermilab-MILC-HPQCD Collaboration. While for the D\ensuremath→K case, we successfully describe the data for f+(q2)/f+(0) recently measured by the FOCUS Collaboration.