Angular distributions in $J/\psi (\rho ,\omega )$ states near threshold

Abstract

A resonance X(3872), first observed in the decays $B\to KX$, has been seen to decay to $J/\psi {\pi }^{+}{\pi }^{-}$. The ${\pi }^{+}{\pi }^{-}$ mass spectrum peaks near its kinematic upper limit, prompting speculation that the dipion system may be in a ${\rho }^0$. The decay $X(3872)\to J/\psi \omega$ also has been observed. The reaction $\gamma \gamma \to J/\psi {\pi }^{+}{\pi }^{-}$ has been studied. Consequently, angular distributions in decays of $J/\psi ({\rho }^0,\omega )$ states near threshold are of interest, and results are presented.

Comments: 10 pages, no figures. To be submitted to Phys. Rev. D