The lightest hybrid meson supermultiplet in QCD

We interpret the spectrum of meson states recently obtained in nonperturbative lattice QCD calculations in terms of constituent quark-antiquark bound states and states, called ``hybrids'', in which the qq pair is supplemented by an excitation of the gluonic field. We identify a lightest supermultiplet of hybrid mesons with J^PC= (0, 1, 2) ^-+, 1^-- built from a gluonic excitation of chromomagnetic character coupled to qq in an S-wave. The next lightest hybrids are suggested to be quark orbital excitations with the same gluonic excitation, while the next distinct gluonic excitation is significantly heavier. Existing models of gluonic excitations are compared to these findings and possible phenomenological consequences explored.