Hybrid quarkonia with dynamical sea quarks

We present a dynamical lattice calculation with two flavors for bottomonium states with an additional gluonic excitation. Using improved actions for the quarks and gauge fields at a lattice spacing of $a\approx 0.1\hspace{0.5em}\mathrm{fm},$ we find 10.977(61)(62) GeV for the energy of the lowest lying $b\overline{b}g$ hybrid, where the first error is statistical and the second denotes the systematic uncertainty due to the determination of scale. In a parallel quenched simulation we demonstrate explicitly that vacuum polarization effects are less than 10% of the splitting with the ground state.