Mesons and hybrids in a relativistic many body theory

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Cotanch, Stephen R.
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American Institute of Physics
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Using a field theoretical, QCD inspired Hamiltonian formulated in the Coulomb gauge, relativistic many-body calculations are reported which reproduce the semiquantitative features of the observed meson and lattice glueball spectrums. Dynamical chiral symmetry breaking is achieved utilizing a BCS vacuum ansatz, yielding gap equations and realistic quark (and gluon) constituent masses and condensates. The excited hadron states are obtained by diagonalizing the effective Hamiltonian in a truncated Fock space using both the TDA and RPA. The meson spectrum, for a variety of spin and parities, is reasonably well described. In general, the two approaches differ minimally, except for the TT and 77 where only the RPA yields correct properties and a Goldstone boson in the chiral limit. Our unified model also describes hybrids and a three-body TDA calculation predicts exotic and non-exotic hybrid states all above 2 GeV. Our results are consistent with lattice and flux tube hybrid masses, suggesting that the recently observed 1~+ exotics below 2 GeV have an alternative, perhaps four quark, structure.
© 2000 American Institute of Physics. This work is supported by grants DOE DE-FG02-97ER41048 and NSF INT- 9807009. Supercomputer time is provided by NERSC. Conference on Intersections of Particle and Nuclear Physics (7.2000.Quebec, Canada)
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1. A. P. Szczepaniak, E. S. Swanson, C.-R. Ji, and S. R. Cotanch, Phys. Rev. Lett. 76, 2011 (1996). 2. F. J. Llanes-Estrada and S. R. Cotanch, Phys. Rev. Lett. 84, 1102 (2000) and references therein. 3. G. S. Adams et al. (E852 Collaboration) Phys. Rev. Lett. 81, 5760 (1998); D. R. Thompson et al. (E852 Collaboration) Phys. Rev. Lett. 79, 1630 (1997). 4. C. McNeile, hep-lat/9904013 (1999).