Heavy hybrid states from NRQCD

Abstract

We present a quenched lattice calculation for the lowest lying g-hybrid states in the framework of NRQCD using the leading order Hamiltonian up to O(m upsilon(2)). We demonstrate the existence of a nearly degenerate rotational band of states with an excitation energy approximately 1.6 GeV above the Y ground state. This lies around the (j)*-threshold, but well above the -threshold. Therefore a heavy hybrid signal may well be detected if the center-of-mass energy in B-factories is raised a few hundred MeV to coincide with other resonances above the 4S state. Our prediction is consistent with most phenomenological models and lattice calculations carried out in the static limit. [S0556-2821(98)50707-2].