Invariant-mass spectrum of O11

The invariant-mass distribution of $^{11}\mathrm{O}$ fragments formed in two-neutron-knockout reactions with a $^{13}\mathrm{O}$ projectile and $^{9}\mathrm{Be}$ target has been further examined. Gating on events where the $^{9}\mathrm{C}$ decay fragments produced following $2p$ emission are recoiled transversely in the projectile's frame improves the overall invariant-mass resolution. The observed peak is now shown to have contributions from at least two $^{11}\mathrm{O}$ levels, in contradiction with the suggestion of Fortune [Phys. Rev. C 99, 051302(R) (2019)]. The data, however, do not differentiate between the ground-state properties obtained by the Gamow coupled-channels calculation and the prompt $2p$-decay model of Fortune. The ground-state $2p$-decay energy is 4.25(6) MeV in a two-level fit to the data, but lower values are possible if more states contribute to the observed spectrum, as suggested in the previous analysis.