%0 Journal Article
%T B_l4 decays and the extraction of |V_ub|
%A Xian-Wei Kang
%A Bastian Kubis
%A Christoph Hanhart
%A Ulf-G. MeiŁżner
%J Physics
%D 2013
%I arXiv
%R 10.1103/PhysRevD.89.053015
%X The Cabibbo-Kobayashi-Maskawa matrix element |V_ub| is not well determined yet. It can be extracted from both inclusive or exclusive decays, like B --> pi (rho) l nu-bar_l. However, the exclusive determination from B --> rho l nu-bar_l, in particular, suffers from a large model dependence. In this paper, we propose to extract |V_ub| from the four-body semileptonic decay B --> pi pi l nu-bar_l, where the form factors for the pion-pion system are treated in dispersion theory. This is a model-independent approach that takes into account the pi-pi rescattering effects, as well as the effect of the rho meson. We demonstrate that both finite-width effects of the rho meson as well as scalar pi-pi contributions can be considered completely in this way.
%U http://arxiv.org/abs/1312.1193v2