Measurement of $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ cross sections at center-of-mass energies from 2.00 to 3.08 GeV

Abstract

Using data corresponding to an integrated luminosity of $651{\mathrm{pb}}^{-1}$ accumulated at 22 center-of-mass energies from 2.00 to 3.08 GeV by the BESIII experiment, the process $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ is studied. The cross sections for $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ are consistent with previous results, but with improved precision. To measure the mass and width of the structure observed in the cross section line shape, a combine fit is performed after enhancing the contribution from $\ddot{I}•f_0(980)$. The fit reveals a structure with the mass of $M=2178\pm 20\pm 5\mathrm{MeV}/c^2$ and the width of $\Gamma =140\pm 36\pm 16\mathrm{MeV}$, where the first uncertainties are statistical and the second ones are systematic.

11 pages, 5 figures