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

Abstract

A resonance X(3872), first observed in the decays $B \to K X$, 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.