Proposal to detect a moving triangle singularity in $\psi (2S)\to {\pi }^{+}{\pi }^{-}{K}^{+}{K}^{-}$ process

Abstract

In this work, we propose that there exists a moving triangle singularity in the $\psi (2S)\to {\pi }^{+}{\pi }^{-}{K}^{+}{K}^{-}$ process, whose position can vary from 1.158 to 1.181 GeV in the invariant mass spectrum of $K^{+}{K}^{-}$. After a precise analysis on this process, it turns out that after doing some cuts on $m_{{\pi }^{+}{\pi }^{-}}$, experiments do have the opportunity to observe this triangle singularity. In addition, when changing the cuts on $m_{{\pi }^{+}{\pi }^{-}}$, the movement of the predicted triangle singularity can also be observed. Thus, we suggest future experiments, especially Super Tau-Charm Facility (STCF), to do an anlysis on the $\psi (2S)\to {\pi }^{+}{\pi }^{-}{K}^{+}{K}^{-}$ process to verify our prediction.