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 …

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” …

The spectrum of hadrons is the manifestation of color confinement of quantum
chromodynamics. Hadronic resonances correspond to poles of the S-matrix. Since 2003 …

Abstract The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany,
provides unique possibilities for a new generation of hadron-, nuclear-and atomic physics …

We study the internal structure of a range of four-quark states with charm quark contributions
using a two-body Bethe–Salpeter equation. Thereby, we examine charmonium-like states …

The X (3872) is the first and the most interesting one amongst the abundant XYZ states. Its
mass coincides exactly with the D 0 D¯* 0 threshold with an uncertainty of 180 keV. Precise …

The resonance state of the baryon, which exists in four isospin () states, has been studied
using the hypercentral constituent quark model (hCQM) with a simple linear potential with …

Excited-state masses of the strange singly charmed baryons are calculated using the
nonrelativistic approach of the hypercentral constituent quark model. The hyper-Coulomb …

The mass-spectra of all-charm tetraquark states [cc][c¯ c¯] with the diquark-antidiquark
configuration are investigated in this study. To determine the fitting parameters for the …

We generalize the framework of Dyson-Schwinger and Bethe-Salpeter equations for four-
quark states to accommodate the case of unequal quark masses. As a first application, we …