Measurement of e+e−→ K+K−π0 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−→ K+K−π0. The Born cross section of the process e+e−→ K+K−π0 and its subprocesses e+e−→ ϕπ0, K*+(892)K− and {K}_2^{ast +} (1430)K− are measured. The results for e+e−→ K+K−π0 and ϕπ0 are consistent with the BaBar measurements and with improved precision. By analyzing the cross sections of the subprocesses e+e−→ K*+(892)K− and {K}_2^{ast +} (1430)K−, a structure with mass MR = (2190 ± 19 ± 37) MeV/c2 and width ΓR = (191 ± 28 ± 60) MeV is observed with a combined statistical significance of 7.1σ. The measured resonance parameters suggest it can be identified as the ϕ(2170), thus the results provide valuable input to understand the internal nature of this state.