Determination of Nucleon Form factors from Baryonic B Decays

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 time-like 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 ${\bar{B}}^0\to n\bar{p}{D}^{\ast +}$ and $\Lambda \bar{p}{\pi }^{+}$ we find a constant ratio of $G_M^n(t)/G_M^p(t)=-1.3\pm 0.4$, which supports the FENICE experimental result. The vector and axial-vector form factors of $p\bar{n}$, $p\bar{p}$ and $n\bar{n}$ pairs due to weak currents are also presented, which can be tested in future experiments.

Comments: 10 pages, 3 figures, final version to be published in PRD