Further insights into the "$ρπ$ puzzle"

Abstract

Based on a systematic investigation of $J/ψ(ψ^\prime)\to VP$, where $V$ and $P$ stand for light vector and pseudoscalar mesons, we identify the role played by the electromagnetic (EM) transitions and intermediate meson loop transitions, which are essential ingredients for understanding the $J/ψ$ and $ψ^\prime$ couplings to $VP$. We show that on the one hand, the EM transitions have relatively larger interferences in $ψ^\prime\to ρπ$ and $K^*\bar{K}+c.c.$ as explicitly shown by vector meson dominance (VMD). On the other hand, the strong decay of $ψ^\prime$ receives relatively larger destructive interferences from the intermediate meson loop transitions. By identifying these mechanisms in an overall study of $J/ψ(ψ^\prime)\to VP$, we provide a coherent understanding of the so-called "$ρπ$ puzzle".