Determination of nucleon form factors from baryonicBdecays

Abstract

It is the first time that the study of three-body baryonic $B$ decays offers an independent determination of the nucleon form factors for the timelike four momentum transfer ($t>0$) region, such as ${G}_{M}^{p,n}(t)$ of vector currents and those of axial ones. Explicitly, from the data of ${\overline{B}}^{0}\ensuremath{\rightarrow}n\overline{p}{D}^{*+}$ and $\ensuremath{\Lambda}\overline{p}{\ensuremath{\pi}}^{+}$ we find a constant ratio of ${G}_{M}^{n}(t)/{G}_{M}^{p}(t)=\ensuremath{-}1.3\ifmmode\pm\else\textpm\fi{}0.4$, which supports the FENICE experimental result. The vector and axial-vector form factors of $p\overline{n}$, $p\overline{p}$ and $n\overline{n}$ pairs due to weak currents are also presented, which can be tested in future experiments.