Hadronic Spectroscopy from the Lattice: Glueballs and Hybrid Mesons

The use of lattice QCD to understand hadron structure is described, with particular emphasis on exploring the role of glue.

I review what lattice QCD simulations have to tell us about the glueball spectrum. Talk given at HEP97, Jerusalem, August 1997.

Recent findings on the spectrum of heavy-quark mesons from computer simulations of quarks and gluons in lattice QCD are summarized, with particular attention to quark-antiquark states bound by an excited gluon field. The validity of a Born-Oppenheimer treatment for such systems is discussed. Recent results on glueball masses, the light-quark 1-+ hybrid meson mass, and the static three-quark potential are summarized.

The status of lattice determinations of quarkonia and hybrid meson spectra is presented and compared with experiment. Both quenched and unquenched results are discussed. Hybrid meson decays are considered.

Many new results on hadron spectra have been appearing in the past few years thanks to improved experimental techniques and searches in new channels. New theoretical techniques including refined methods of lattice QCD have kept pace with these developments. Much has been learned about states made of both light (u, d, and s) and heavy (c, b) quarks. The present review treats light-quark mesons, glueballs, hybrids, particles with a single c or b quark, charmonium, and bottomoni...

The existence of non-q\bar{q} hadrons such as glueballs and hybrids is one of the most important qualitative questions in QCD. The COMPASS experiment offers the possibility to unambiguously identify such states and map out the glueball and hybrid spectrum. In this review I discuss the expected properties of glueballs and hybrids and how they might be produced and studied by the COMPASS collaboration.

We review lattice QCD results for glueballs (including a discussion of mixing with scalar mesons), hybrid mesons and exotic mesons (such as $B_s B_s$ molecules).

Nonperturbative QCD approach is systematically derived starting from the QCD Lagrangian. Treating spin effects as a perturbation, one obtains the universal effective Hamiltonian describing mesons, hybrids and glueballs. Constituent mass of quark and gluon is calculated via string tension. The resulting spectrum of mesons, hybrids and glueballs obtained is in good overall agreement with lattice data and experiment.

I review the results of hadron spectroscopy calculations from lattice QCD for an intended audience of low energy hadronic physicists. I briefly introduce the ideas of numerical lattice QCD. The various systematic errors, such as the lattice spacing and volume dependence, in lattice QCD calculations are discussed. In addition to the discussion of the properties of ground state hadrons, I also review the small amount of work done on the spectroscopy of excited hadrons and the e...

I review recent Lattice results. In particular, the confinement mechanism and string breaking, glueballs and hybrid mesons as well as light hadron spectroscopy are discussed.