Measurement of $e^{+}{e}^{-}\to K^{+}{K}^{-}\ddot{I}{€}^0$ cross section and observation of a resonant structure

Abstract

Based on $e^{+}{e}^{-}$ collision data collected by the BESIII detector at the BEPCII collider at center-of-mass energies from 2.000 to 3.080 GeV, a partial-wave analysis is performed for the process $e^{+}{e}^{-}\to K^{+}{K}^{-}\ddot{I}{€}^0$. The Born cross section of the process $e^{+}{e}^{-}\to K^{+}{K}^{-}\ddot{I}{€}^0$ and its subprocesses $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{€}^0$, $K^{\ast }(892)K$ and $K_2^{\ast }(1430)K$ are measured. The results for $e^{+}{e}^{-}\to K^{+}{K}^{-}\ddot{I}{€}^0$ and $\ddot{I}•\ddot{I}{€}^0$ are consistent with the BaBar measurements and with improved precision. By analyzing the cross section, of the subprocesses $e^{+}{e}^{-}\to$ $K^{\ast }(892)K$ and $K_2^{\ast }(1430)K$, a structure with mass $M_R$ = (2208 $\pm$ 19 $\pm$ 24) MeV/$c^2$ and width $\hat{I}{“}_R$ = (168 $\pm$ 24 $\pm$ 39) MeV is observed with a combined statistical significance of 7.6$\ddot{I}ƒ$. The measured resonance parameters suggest it can be identified as the $\ddot{I}•(2170)$, thus the results provide valuable input to understand the internal nature of this state.

arXiv admin note: text overlap with arXiv:2001.04131