Study of $e^{+}{e}^{-}\to p\bar{p}$ in the vicinity of $\ddot{I}ˆ(3770)$

Abstract

Using 2917 ${\mathrm{pb}}^{-1}$ of data accumulated at 3.773~$\mathrm{GeV}$, 44.5~${\mathrm{pb}}^{-1}$ of data accumulated at 3.65~$\mathrm{GeV}$ and data accumulated during a $\ddot{I}ˆ(3770)$ line-shape scan with the BESIII detector, the reaction $e^{+}{e}^{-}\to p\bar{p}$ is studied considering a possible interference between resonant and continuum amplitudes. The cross section of $e^{+}{e}^{-}\to \ddot{I}ˆ(3770)\to p\bar{p}$, $\ddot{I}ƒ(e^{+}{e}^{-}\to \ddot{I}ˆ(3770)\to p\bar{p})$, is found to have two solutions, determined to be ($0.059\pm 0.032\pm 0.012$) pb with the phase angle $\ddot{I}•=(255.8\pm 37.9\pm 4.8{)}^{\circ }$ ($<$0.11 pb at the 90% confidence level), or $\ddot{I}ƒ(e^{+}{e}^{-}\to \ddot{I}ˆ(3770)\to p\bar{p})=(2.57\pm 0.12\pm 0.12$) pb with $\ddot{I}•=(266.9\pm 6.1\pm 0.9{)}^{\circ }$ both of which agree with a destructive interference. Using the obtained cross section of $\ddot{I}ˆ(3770)\to p\bar{p}$, the cross section of $p\bar{p}\to \ddot{I}ˆ(3770)$, which is useful information for the future PANDA experiment, is estimated to be either ($9.8\pm 5.7$) nb ($<17.2$ nb at 90% C.L.) or $(425.6\pm 42.9)$ nb.