$B$ to $π$ Form Factors in collinear factorization approach

Simple item page
dc.creatorYeh, Tsung-Wen
dc.date2008-12-31
dc.date.accessioned2026-07-07T12:23:41Z
dc.date.available2026-07-07T12:23:41Z
dc.descriptionThe form factors for semi-leptonic B decays, $\bar{B}\toπl\barν_l$, are calculated under collinear factorization approach. The end-point divergences are regularized by a $ξ$-regularization, where $ξ$ means the collinear fraction of the spectator anti-quark of the $\bar{B}$ meson. The form factors are calculated up-to $O(α_{s}/m_{B})$. The complete $O(1/m_{B})$ contributions from the $π$ meson are calculated explicitly by a collinear expansion method. A well-defined power expansion scheme is built such that the $O(1/m_{B})$ contributions are about 30% of the leading order contributions. A small value $F_+(0)=0.164$ is found. This confirms the SCET result $F_+(0)=0.17$ from $B\toππ$ decays. The form factors are calculated for {\normalsize $0\leq q^{2}\leq16 \text{GeV}^{2}$}, where $q^2$ is the invariant mass of the lepton pair in $\bar{B}\toπl\barν_l$. An extrapolation of the form factors to $q^{2}>16 \text{GeV}^{2}$ is made to obtain {\normalsize $|V_{ub}|^{-2}\int_{0}^{26.42 \text{GeV}^{2}}dq^{2}(dΓ/dq^{2})_{\text{th}}=(5.71\pm 0.91)ps^{-1}$}. We determine $|V_{ub}|=(3.95\pm 0.13_{\text{exp}}\pm 0.32_{\text{th}})\times 10^{-3}$ from the world averaged branching ratio $Br(\bar{B}\toπl\barν_{l})=(1.36\pm 0.09)\times 10^{-4}$.
dc.description45 pages, 5 figures, 3 tables
dc.identifierhttps://arxiv.org/abs/0901.0064
dc.identifierhttp://arxiv.org/abs/0901.0064
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/214072
dc.subjectHigh Energy Physics - Phenomenology
dc.title$B$ to $π$ Form Factors in collinear factorization approach
dc.typetext

Files

Collections

arXiv