Related papers: Hunting exotics
Exotic mesons with hidden strange ($s\bar s$) and heavy quark pairs ($Q\bar Q$), where $Q=c,b$, are considered as diquark-antidiquark systems, $(Qs)(\bar Q\bar s)$. Taking into account that these states can recombinate into two-meson ones,…
We perform systematical investigations of heavy flavor tetraquark systems, including fully heavy $QQ\bar Q\bar Q$ ($Q=b,c$), doubly heavy $QQ^{(\prime)}\bar q\bar q$ ($q=u,d$), and singly heavy $Qs\bar q\bar q$ tetraquark systems, within…
All the available experimental information on open charm and beauty mesons is used to classify the observed states in heavy quark doublets. The masses of some of the still unobserved states are predicted, in particular in the beauty sector.…
The possibility of using the charm system to search for new physics is addressed. Phenomena such as $D^0-\bar D^0$ mixing and rare decays of charmed mesons are first examined in the Standard Model to test our present understanding and to…
We study charmonium ($c\bar c n\bar n$), bottomonium ($b\bar b n\bar n$) and exotic ($cc\bar n\bar n$ and $bb\bar n\bar n$) four-quark states by means of a standard non-relativistic quark potential model. We look for possible bound states.…
Group theoretic method for the systematic study of five-quark states with meson-baryon ($q\bar{q}-q^3$) configuration is developed. The calculation of matrix elements of many body Hamiltonian is simplified by transforming the physical bases…
In the framework of the color-magnetic interaction model, we have systematically calculated the mass splittings for the S-wave triply heavy pentaquark states with the configuration $qqQQ\bar{Q}$ $(Q=c,b;q=u,d,s)$. Their masses are estimated…
The experimental information on the search for non $q \bar q$ mesons as glueballs, hybrids and multiquark states is reviewed. Candidate states which are particularly amenable to detailed study by accumulating large samples of $J/\psi$,…
In this study, the spectroscopic parameters of the exotic molecular states composed of mesons containing two heavy quarks (scalar-axial and pseudoscalar-axial meson combinations) are investigated within QCD sum rules. Our findings reveal…
The relativistic four-quark equations are found in the framework of coupled-channel formalism. The dynamical mixing of the meson-meson states with the four-quark states is considered. The approximate solutions of these equations using the…
Many new results on open and hidden charm spectroscopy have been obtained recently. We present a short review of the experimental findings in the meson sector, of the theoretical interpretations and of the open problems, with a discussion…
The $B_c ^+$ family of $(c\bar{b})$ mesons with beauty and charm is of special interest among heavy quarkonium systems. The $B_c ^+$ mesons are intermediate between $(c\bar{c})$ and $(b\bar{b})$ states both in mass and size, so many…
A menage a trois is very different from an ordinary family. Similarly, exotic hadrons with both qq and qbar q pairs have important color-space correlations that are completely absent in ordinary mesons and baryons. The presence of both…
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…
In this work, a color structure dependent flip-flop potential is developed for the two quarks and two antiquarks system. Then, this potential is applied to a microscopic quark model which, by integrating the internal degrees of freedom, is…
These are the mini-proceedings of the CHARMEX workshop. The meeting focused on recent developments in charm spectroscopy, especially on the possible role of the states that do not fit into the quark model classification, the so-called…
We review our results in Refs.[1,2] for the masses and couplings of heavy-light DD(BB)-like molecules and (Qq)(Qq)-like four-quark states from relativistic QCD Laplace sum rules (LSR) where next-to-next-to-leading order (N2LO) PT…
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…
Many of the $XYZ$ resonances observed by the Belle, Babar, CLEO and BESIII collaborations in the past decade are difficult to interpret as conventional quark-antiquark mesons, motivating the consideration of scenarios such as multi-quark…
In this feature article we summarise and highlight aspects of the treatment of four-quark states with functional methods. Model approaches to those exotic mesons almost inevitably have to assume certain internal structures, e.g. by grouping…