  Recent inelastic neutron scattering (INS) experiments of the triangular
antiferromagnet Ba$_3$CoSb$_2$O$_9$ revealed strong deviations from
semiclassical theories. We demonstrate that key features of the INS data are
well reproduced by a parton Schwinger boson theory beyond the saddle-point
approximation. The measured magnon dispersion is well reproduced by the
dispersion of two-spinon bound states (poles of the emergent gauge fields
propagator), while the low-energy continuum scattering is reproduced by a
quasifree two-spinon continuum, suggesting that a free-spinon gas is a good
initial framework to study magnetically ordered states near a quantum melting
point.
