Many-body Coulomb gauge exotic and charmed hybrids

Abstract

Utilizing an effective QCD Coulomb gauge Hamiltonian with linear confinement specified by lattice, we report a relativistic many-body calculation for the light exotic and charmed hybrid mesons. The Hamiltonian successfully describes both quark and gluon sectors, with vacuum and quasiparticle properties generated by a BCS transformation and more elaborate TDA and RPA diagonalizations for the meson (q¯q ) and glueball (gg) masses. Hybrids entail a computationally intense relativistic three quasiparticle (q ¯ qg) calculation with the 9-dimensional Hamiltonian matrix elements evaluated variationally by Monte Carlo techniques. Our new TDA (RPA) spectrum for the nonexotic 1−− charmed (c ¯ c and c ¯cg) system provides an explanation for the overpopulation of the observed J/ψ states. For the important 1−+ light exotic channel we obtain hybrid masses above 2 GeV, in broad agreement with lattice and flux tube models, indicating that the recently observed resonances at 1.4 and 1.6 GeV are of different, perhaps four quark, structure.