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

Abstract

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. Many models for their composition have been suggested, but perhaps discovering their bottom counterparts could shed much light on the issue. The narrow state, $X_b$ may be searched for at the Tevatron via $p\bar p \to \pi^+\pi^-\Upsilon + X$, with the LHC much more promising. The state $Y_b$ can be searched for at B factories via radiative return $e^+e^- \to \gamma_{\rm ISR} + \pi^+\pi^-\Upsilon$ on $\Upsilon(5S)$, or by $e^+e^- \to \pi^+\pi^-\Upsilon$ direct scan.