The spectrum of heavy-quark hybrid mesons

(neglecting light quark loops)

K.J. Juge, J. Kuti, and C. Morningstar, Phys. Rev. Lett. 82, 4400 (1999).

(a) Static-quark potentials and radial probability densities against quark-antiquark separation r for r₀^-1=450 MeV. (b) Spin-averaged b-bar b spectrum in the leading Born-Oppenheimer approximation (light quarks neglected). Solid lines indicate experimental measurements. Short dashed lines indicate the conventional S and P state masses obtained from the Schrodinger equation with the Sigma_g⁺ potential for quark mass M_b=4.58 GeV. Dashed-dotted lines indicate the hybrid quarkonium states obtained from the Pi_u (L=1,2,3) and Sigma_u^- (L=0,1,2) potentials. Repeating the same analysis in the charmonium system, we find the lowest Pi_u hybrid 1.19 GeV above the spin averaged ground state. Note that the inclusion of light quark loops will dramatically change this spectrum.