Detecting the pure triangle sigularity effect through the $\ddot{I}ˆ(2S)\to p\bar{p}\hat{I}\cdot /p\bar{p}\ddot{I}{€}^0$ process

Abstract

In this work, the triangle singularity mechanism is investigated in the $\ddot{I}ˆ(2S)\to p\bar{p}\hat{I}\cdot /p\bar{p}\ddot{I}{€}^0$ process. The triangle loop composed by $J/\ddot{I}ˆ$, $\hat{I}\cdot$ and $p$ has a singularity in the physical kinematic range for the $\ddot{I}ˆ(2S)\to p\bar{p}\hat{I}\cdot /p\bar{p}\ddot{I}{€}^0$ process, and it would generate a very narrow peak in the invariant mass spectrum of $p\hat{I}\cdot (\ddot{I}€)$ around $1.56387$ GeV, which is far away from both the threshold and relative resonances. In these processes, all the involved vertices are constrained by the experimental data. Thus, we can make a precise model independent prediction here. It turns out that the peak in the $p\hat{I}\cdot$ invariant mass spectrum is visible, while it is very small in the $p\ddot{I}{€}^0$ invariant mass spectrum. We expect this effect shown in $p\bar{p}\hat{I}\cdot$ final state can be observed by the Beijing Spectrometer (BESIII) and Super Tau-Charm Facility (STCF) in the future.