Search for Bottom Counterparts of X(3872) and Y(4260) via ${\pi }^{+}{\pi }^{-}{\rm Y}$

George W. S. Hou

The X(3872) and Y(4260), both discovered in ${\pi }^{+}{\pi }^{-}J/\psi$ mode, are rather unusual: $X_c\equiv X(3872)$ is very narrow, while $Y_c\equiv Y(4260)$ has large $Y_c\to {\pi }^{+}{\pi }^{-}J/\psi$ width…