1111.4055 (Jinlin Fu et al.)

Study of the electromagnetic transitions $J/ψ\rightarrow P l^+l^-$    [PDF]

Jinlin Fu, Hai-Bo Li, Xiaoshuai Qin, Mao-Zhi Yang

We study the electromagnetic Dalitz decay modes of $J/\psi \rightarrow P l^+l^-$ ($P= \pi^0$, $\eta$ or $\eta^\prime$). In these decays, the lepton pairs are formed by internal conversion of an intermediate virtual photon with invariant mass $m_{l^+l^-}$. Study of the effective-mass spectrum of the $l^+l^-$ will shed light on the dynamic transition form factor $F_{J/\psi P}(q^2)$ ($q^2 = m^2_{l^+l^-}$), which characterizes the electromagnetic structure arising at the vertex of the transition $J/\psi$ to pseudoscalar. In this paper, we derive the angular distribution and $q^2$-dependent decay rate of the conversion decay. For the first time, we use the usual pole approximation for the form factor to estimate the decay rate of $J/\psi \rightarrow P l^+l^-$. We suggest that these electromagnetic Dalitz decays can be searched for at BESIII experiment with huge $J/\psi$ data set.

View original: http://arxiv.org/abs/1111.4055