Glueballs, hybrids and multiquark states are predicted as bound states in models guided by
quantum chromo dynamics (QCD), by QCD sum rules or QCD on a lattice. Estimates for the …

We discuss theoretical predictions for the existence of exotic (non-quark-model) mesons and
review prominent experimental candidates. These are especially the f0 (1500) and f0 (1710) …

We interpret the spectrum of meson states recently obtained in nonperturbative lattice QCD
calculations in terms of constituent quark-antiquark bound states and states, called “hybrids” …

A review of the theoretical and experimental status of hybrid hadrons is presented. The
states π 1 (1400), π 1 (1600), and π 1 (2015) are thoroughly reviewed, along with …

We study hadrons with a 2-gluon valence component, emphasizing states not found in the
quark model. We predict that 0++, 0−+, 1++, and the particularly interesting 1−+ glueballs …

Quantum Chromodynamics, the theory of quarks and gluons, whose interactions can be
described by a local SU (3) gauge symmetry with charges called “color quantum numbers” …

We review how lattice QCD can contribute to the prediction and the comprehension of
tetraquarks, pentaquarks and related exotic hadrons such as hybrids, with at least one …

A systematic enumeration of the glueball spectrum of QCD and other SU (n) gauge theories
yields JPC= odd−+ even+−, and 0−− states in addition to the usual quark model states …

The quark model was formulated in 1964 to classify mesons as bound states made of a
quark–antiquark pair, and baryons as bound states made of three quarks. For a long time all …

Lattice QCD predictions have motivated several recent studies of the mixing between the
predicted J^PC=0^++ glueball and a q̄q nonet in the 1.3→1.7 GeV region. We show that …