Heavy Hybrids from NRQCD

Abstract

We present a quenched lattice calculation for the lowest lying $b\bar{b}g$-hybrid states in the framework of NRQCD using the leading order Hamiltonian up to $\mathcal{O}(m{v}^2)$. We demonstrate the existence of a nearly degenerate rotational band of states with an excitation energy approximately 1.6 GeV above the ${\rm Y}$ ground state. This lies around the $B{\bar{B}}_J^{\ast }$-threshold but well above the $B\bar{B}$-threshold. Therefore a heavy hybrid signal may well be detected if the centre-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.

Comments: 9 pages, LaTeX2e, 2 figures, uses styles [11pt, a4wide, epsf]