Observation of e⁺e⁻ → ωχ_{c1, 2} near √s̅ = 4.42 and 4.6 GeV

Based on data samples collected with the BESIII detector operating at the BEPCII storage ring at center-of-mass energies √s̅ > 4.4 GeV, the processes e⁺e⁻ → ωχ(c1,2) are observed for the first time. With an integrated luminosity of 1074 pb⁻¹ near √s̅ = 4.42 GeV, a significant ωχ(c2) signal is found, and the cross section is measured to be (20.9 ± 3.2 ± 2.5) pb. With 567 pb⁻¹ near √s̅ = 4.6 GeV, a clear ωχ(c1) signal is seen, and the cross section is measured to be (9.5 ± 2.1 ± 1.3) pb, while evidence is found for an ωχ(c2) signal. The first errors are statistical, and the second are systematic. Due to low luminosity or low cross section at other energies, no significant signals are observed. In the ωχ(c2) cross section, an enhancement is seen around √s̅ = 4.42 GeV. Fitting the cross section with a coherent sum of the ψ(4415) Breit-Wigner function and a phase-space term, the branching fraction B(ψ(4415) → ωχ(c2)) is obtained to be of the order of 10⁻¹.