Study of the e+e − → π + π − ω process at center-of-mass energies between 4.0 and 4.6 GeV

Using 15.6 fb −1 of e + e − collision data collected at twenty-four center-of-mass energies from 4.0 to 4.6 GeV with the BESIII detector, the helicity amplitudes of the process e + e − → π + π − ω are analyzed for the first time. Born cross section measurements of two-body intermediate resonance states with statistical significance greater than 5σ are presented, such as f 0(500), f 0(980), f 2(1270), f 0(1370), b 1(1235) ± , and ρ(1450) ± . In addition, evidence of a resonance state in e + e − → π + π − ω production is found. The mass of this state obtained by line shape fitting is about 4.2 GeV/c 2, which is consistent with the production of ψ(4160) or Y(4220).