Related papers: Theory Concepts for Heavy Exotic Mesons
The XYZ mesons are unexpected mesons containing a heavy quark-antiquark pair that have been discovered during the last decade. The models for the XYZ mesons that have been proposed include conventional quarkonium, quarkonium hybrids, and…
A brief survey is presented of recently discovered hadrons, some of them presumably demonstrating a new kind of internal structure. This includes : spin-singlet quarkonium, mesons with unexpected mass or width, baryons with two heavy…
In the last decades, the number of exotic candidates which are beyond the conventional quark model has grown dramatically. At the same time, numerous theoretical interpretations, such as tetraquark, hybrid, hadroquarkonium and hadronic…
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…
I review here the most recent results about the observation and the study of hadronic bound states that do not fit well in the standard quarkonium picture. Several new states have been observed in the last few years, at B-, tau-Factories…
Scores of exotic hadrons, particularly tetraquarks and pentaquarks in the heavy-quark sector, have been observed in the past 20 years, and more continue to be discovered to this day. Unlike mesons and baryons, such exotics are not mandated…
Exotic hadrons are important because their existence or absence can provide important clues to understanding how QCD makes hadrons from quarks and gluons. The first experimentally confirmed exotic will be the first hadron containing both…
The last few years have been witness to a proliferation of new results concerning heavy exotic hadrons. Experimentally, many new signals have been discovered that could be pointing towards the existence of tetraquarks, pentaquarks, and…
The molecular picture and the constituent-quark model of exotic hadrons are reviewed, with application to the states recently discovered in the hidden-charm and hidden beauty sectors, and to other configurations.
Some recent discoveries in the spectroscopy of hadrons containing heavy quarks, and some of their theoretical interpretations, are reviewed.
The potential of decays of mesons containing heavy quarks [including $B$ mesons and the $\Upsilon(1S)$] for producing final states of matter with unusual quark configurations, such as $q q \bar q \bar q$ or $q q q q \bar q$, is…
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…
I discuss several recent highly accurate theoretical predictions for masses of baryons containing the b quark, as well as an effective supersymmetry between heavy quark baryons and mesons. I also suggest some possibilities for observing…
I review the properties of mesons with one heavy quark. I start by examining the predicted masses and widths in the context of the quark model and heavy quark effective theory. Some recent experimental results are described and I conclude…
Exotic hadrons are a new class of hadronic states whose properties do not allow them to be classified as conventional quark-antiquark mesons or three quark baryons. Finding new and understanding established exotic states is the most…
A review is presented of past and recent attempts to build multiquark states within current models already describing ordinary mesons and baryons. This includes: coherence in the chromomagnetic interaction, tetraquarks with two heavy…
Exotic hadron states beyond the conventional $qqq$ baryon and $q\bar{q}$ meson configurations are well expected from QCD. Having been successful in the past decades, the heavy quarkonium sector is proved to be an ideal place for the study…
In recent years data have been accumulated at various experiments about states in the heavy quarkonium mass range that seem to be inconsistent with the most simple variants of the quark model. In this contribution it is demonstrated that…
Since nine years experiments have been observing a host of exotic states decaying into heavy quarkonia. The interpretation of most of them still remains uncertain and, in some cases, controversial, notwithstanding a considerable progress…
We present a plausible mechanism for the origin of the $XYZ$ mesons in the heavy meson spectra within a standard quark-model picture. We discuss the conditions required for the existence of four--quark bound states or resonances…