Properties of the ${\eta }_q$ leading-twist distribution amplitude and its effects to the $B/D^{+}\to {\eta }^{(\prime )}{\ell }^{+}{\nu }_{\ell }$ decays

Dan-Dan Hu, Xing-Gang Wu, Hai-Bing Fu +3

The ${\eta }^{(\prime )}$-mesons in the quark-flavor basis are mixtures of two mesonic states $|{\eta }_q⟩=|\bar{u}u+\bar{d}d⟩/\sqrt{2}$ and $|{\eta }_s⟩=|\bar{s}s⟩$. In th…