Spectroscopy of$Q\bar Qg$ hybrid mesons

Abstract

Hybrid mesons composed of a quark, an antiquark, and a gluon are studied in the case of heavy quarks. Their masses are calculated with the potential model which can interpret heavy quarkonium spectroscopy. The ground state of the hybrid mesons$c\bar cg$ and$b\bar bg$ is found to be almost spherically symmetric, whereas that of$t\bar tg$ is two-centered as anH ⁺₂ molecule. The$b\bar bg\left[ {t\bar tg} \right]$ ground state turns out to have a mass below the$B\bar B\left[ {T\bar T} \right]$ threshold. The excited states contain 0⁻⁻, 1⁻⁺ exotic states and 1⁻⁻ states which may be examined bye ⁺ e ⁻ colliders.