The existence and properties of the sigma meson have been controversial for almost six
decades, despite playing a central role in the spontaneous chiral symmetry of QCD or in the …

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 have performed the most comprehensive resonance-model fit of π-π-π+ states using the
results of our previously published partial-wave analysis (PWA) of a large data set of …

The COMPASS Collaboration at CERN has measured diffractive dissociation of 190 GeV/c
pions into the π-π-π+ final state using a stationary hydrogen target. A partial-wave analysis …

We present a generalization of the hyperspherical harmonic formalism to study systems
made of quarks and antiquarks of the same flavor. This generalization is based on the …

We present an exact calculation of S and P wave QQ n¯ n¯ states using different standard
nonrelativistic quark-quark potentials. We explore in detail the charm and bottom sectors …

The recent B factories measurements of new states exhibit, in most of the decays,
charmonium-like resonances. Among them we study the JPC= 1--hidden charm resonances …

In the present work, the mass spectra of the light mesons, the kaons (us¯), and
strangeonium (ss¯) is systematically studied within the framework of Regge …

A generalized linear sigma model for low-energy QCD is employed to study the quark
structure of eight low-lying scalar isomultiplets as well as eight low-lying pseudoscalar …

We present an exact method to study four-quark systems based on the hyperspherical
harmonics formalism. We apply it to several physical systems of interest containing two …