Angular asymmetries in $B\to \Lambda \bar{p}M$ decays

Abstract

The forward-backward angular asymmetry (${\mathcal{A}}_{FB}$) for ${\bar{B}}^0\to \Lambda \bar{p}{\pi }^{+}$ measured by Belle has presented an experimental value in the range of $-30\%$ to $-50\%$. In our study, we find that ${\mathcal{A}}_{FB}[{\bar{B}}^0\to \Lambda \bar{p}{\pi }^{+}(B^{-}\to \Lambda \bar{p}{\pi }^0)]$ can be as large as $(-14.6_{-1.5}^{+0.9}\pm 6.9)\%$. In addition, we present ${\mathcal{A}}_{FB}[{\bar{B}}^0\to \Lambda \bar{p}{\rho }^{+}(B^{-}\to \Lambda \bar{p}{\rho }^0)]=(4.1_{-0.7}^{+2.8}\pm 2.0)\%$ as the first prediction involving a vector meson in the charmless $B\to \mathbf{B}{\bar{\mathbf{B}}}^{\prime }M$ decays. While ${\mathcal{A}}_{FB}(B\to \Lambda \bar{p}M)$ indicates an angular correlation caused by the rarely studied baryonic form factors in the timelike region, LHCb and Belle~II are capable of performing experimental examinations.

Comments: 13 pages, 2 figures, 3 tables, published version in PRD