Related papers: Unraveling the pattern of the $XYZ$ mesons
To illustrate the campaign to understand heavy quarkonium systems, I focus on a puzzling new state, $X(3872) \to \pi^+\pi^- J/\psi$. Studying the influence of open-charm channels on charmonium properties leads us to propose a new charmonium…
In this talk we present some recent studies of multiquark components in the charmonium sector. We study the possible existence of compact four quark-states and meson-meson molecules in the charmonium spectroscopy.
The recent observation of higher quark combinations, tetraquarks and pentaquarks, is a strong indication of more exotic hadrons. Using Z_{2} and Z_{3} symmetries and standard model data, a general quark combination producing new hadronic…
In this contribution, we discuss the possible importance of continuum-coupling (or threshold) effects in heavy quarkonium spectroscopy. Our calculations are carried out in a coupled-channel model, where meson-meson higher Fock (or…
Tremendous progress has been made experimentally in the hadron spectrum containing heavy quarks in the last two decades. It is surprising that many resonant structures are around thresholds of a pair of heavy hadrons. There should be a…
Although the spectra of heavy quarkonium systems has been successfully explained by certain QCD motivated potential models, their strong decays are difficult to deal with. We perform a microscopic calculation of charmonium strong decays…
To obtain an exact solution of a four-body system containing two quarks and two antiquarks interacting through two-body terms is a cumbersome task that has been tackled with more or less success during the last decades. We present an exact…
Observations of new charmonium(-like) and bottomonium(-like) states (sometimes refered to as "XYZ" states) at e+e- colliders have changed our picture of quarkonia systems as QCD bound states. Potential models with a linear confinement…
In recent years, the discovery in quarkonium spectrum of several states not predicted by the naive quark model has awakened a lot of interest. A possible description of such states requires the enlargement of the quark model by introducing…
The analytical forms of the interaction potentials between one S-wave and one P-wave heavy mesons as well as the potentials between two P-wave heavy mesons are deduced based on a chiral quark model. Our results explicitly show the…
Since the discovery of the $J/\psi$, the quark model was very successful in describing the spectrum and properties of heavy mesons including only $q\bar q$ components. However since 2003, with the discovery of the $X(3872)$, many states…
A number of charmonium- and bottomonium-like meson states have been observed that have properties that do not match well to expectations for the simple quark-antiquark substructure suggested by the constituent quark model. Some of them are…
For many decades after the invention of the quark model in 1964 there was no evidence that hadrons are formed from anything other than the simplest pairings of quarks and antiquarks, mesons being formed of a quark-antiquark pair and baryons…
Heavy quarks provide a new dimension to QCD, allowing tests of fundamental theory, the nature of color confinement, and the production of new exotic multiquark states. I also discuss novel explanations for several apparently anomalous…
A discussion is presented of the estimates of the energy and width of resonances in constituent models, with focus on the tetraquark states containing heavy quarks.
The spectroscopy of light, strange baryons have been an important aspect with still unknown resonances and intrinsic baryonic properties. The present document is focused on the $\Delta$ baryons unlike earlier work, here all the four isospin…
The $\Upsilon(10753)$ state has been recently observed by the Belle and Belle~II collaborations with enough global significance to motivate an assessment of the high-energy spectrum usually predicted by any reasonable \emph{na\"ive} quark…
Many unexpected charmonium-like states have recently been observed above the $D\overline{D}$ threshold, which features can't be explained by the conventional quark models. These states are known as XYZ mesons. The study of the radiative…
We study tetraquarks in large $N$ QCD with heavy quarks, in the domain where non-relativistic quantum mechanics offers an adequate approximation. Within the regime of validity of the Born-Oppenheimer approximation, we systematically study…
The hidden-charm tetraquarks with strangeness, $c\bar{c}s\bar{q}$ $(q=u,\,d)$, in $J^P=0^+$, $1^+$ and $2^+$ are systematically investigated in the framework of real- and complex-scaling range of a chiral quark model, whose parameters have…