Study of the process e+e- ? ?? at center-of-mass energies between 2.00 and 3.08 GeV

Abstract

The process e(+)e(-) -> phi eta is studied at 22 center-of-mass energy points (root 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(-) -> phi eta is found to be consistent with BABAR measurements, but with improved precision. A resonant structure around 2.175 GeV is observed with a significance of 6.9 sigma with mass (21635 +/- 6.2 +/- 3.0) MeV/c(2) and width (31.1(-11.6)(+21.1) +/- 1.1) MeV, where the first uncertainties are statistical and the second are systematic.