B_l4 decays and the extraction of |V_ub|
Abstract
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.
Keywords
Cite
@article{arxiv.1312.1193,
title = {B_l4 decays and the extraction of |V_ub|},
author = {Xian-Wei Kang and Bastian Kubis and Christoph Hanhart and Ulf-G. Meißner},
journal= {arXiv preprint arXiv:1312.1193},
year = {2014}
}
Comments
12 pages, 4 figures; v2: Appendix C removed, version published in Phys. Rev. D