The process $e^{ +}e^{ -} \rightarrow \phi\eta$ is studied at 22 center-of-mass energy points ($\sqrt{ s}$) between 2.00 and 3.08 GeV using 715 pb$^{ -1}$ of data collected with the BESIII detector. The measured Born cross section of $e^{ +}e^{ -} \rightarrow \phi\eta$ is found to be consistent with { \textsl{ BABAR}} measurements, but with improved precision. A resonant structure around 2.175 GeV is observed with a significance of 6.9$\sigma$ with mass ($2163.5\pm6.2\pm3.0$) MeV/$c^{ 2}$ and width ($31.1_{ -11.6}^{ +21.1}\pm1.1$) MeV, where the first uncertainties are statistical and the second are systematic.
Categories: hep-ex