Proposal to detect a moving triangle singularity in ψ(2S)→π+π−K+K− process

Abstract

In this work, we propose that there exists a moving triangle singularity in the $\ensuremath{\psi}(2S)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{K}^{+}{K}^{\ensuremath{-}}$ process, whose position can vary from 1.158 to 1.181 GeV in the invariant mass spectrum of ${K}^{+}{K}^{\ensuremath{-}}$. After a precise analysis on this process, it turns out that after doing some cuts on ${m}_{{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}}$, experiments do have the opportunity to observe this triangle singularity. In addition, when changing the cuts on ${m}_{{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}}$, 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 analysis on the $\ensuremath{\psi}(2S)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{K}^{+}{K}^{\ensuremath{-}}$ process to verify our prediction.