Measurement of the $e^{+}{e}^{-}\to p\bar{p}\ddot{I}{€}^0$ cross section at $\sqrt{s}=2.1000-3.0800$ GeV

Abstract

The process $e^{+}{e}^{-}\to p\bar{p}\ddot{I}{€}^0$ is studied at 20 center-of-mass energies ranging from 2.1000 to 3.0800 GeV using 636.8 pb${}^{-1}$ of data collected with the BESIII detector operating at the BEPCII collider. The Born cross sections for $e^{+}{e}^{-}\to p\bar{p}\ddot{I}{€}^0$ are measured with high precision. Since the lowest center-of-mass energy, 2.1000 GeV, is less than 90 MeV above the $p\bar{p}\ddot{I}{€}^0$ energy threshold, we can probe the threshold behavior for this reaction. However, no anomalous threshold enhancement is found in the cross sections for $e^{+}{e}^{-}\to p\bar{p}\ddot{I}{€}^0$.