Related papers: Exotic meson-meson molecules and compact four--qua…
Charmonium, the spectroscopy of c\bar{c} mesons, has recently enjoyed a renaissance with the discovery of several missing states and a number of unexpected charmonium-like resonances. The discovery of these new states has been made possible…
We investigate the pentaquark($P$) exotic baryons as soliton-antiflavored heavy mesons bound states in the limit of infinitely heavy meson mass. Our approach respects the chiral symmetry as well as the heavy quark symmetry. The results…
Models proposed to explain recently discovered heavy-light four-quark states already assume certain internal structures, i.e. the (anti)quark constituents are grouped into diquark/antidiquark clusters, heavy-meson/light-meson clusters…
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…
Inspired by the recent observation of $\chi_{c0}(3930)$, $X(4685)$ and $X(4630)$ by the LHCb Collaboration and some exotic resonances such as $X(4350)$, $X(4500)$, etc. by several experiment collaborations, the $cs\bar{c}\bar{s}$ tetraquark…
Here we investigate the decay patterns of the low-lying hidden strangeness nucleon resonances ($\equiv N_{s\bar{s}}$) to the strangeness channels by employing the chiral Lagrangian approach, where the $N_{s\bar{s}}$ states are treated as…
Considering quantum chromodynamics in the consistent limit of simultaneous correlated increase of the number of colours, $N_{\rm c}$, beyond bounds and decrease of the strong coupling to zero allows for solid statements about qualitative…
We estimate the masses of the 1^{--} heavy four-quark and molecule states by combining exponential Laplace (LSR) and finite energy (FESR) sum rules known perturbatively to lowest order (LO) in alpha_s but including non-perturbative terms up…
The observation of the D_{sJ}^*(2317), D_{sJ}(2460), and SELEX D^*_{sJ}(2632) states with properties differing considerably from what was expected has led to a renewed interest in hadron spectroscopy. In addition to these states,…
The recent reported charmed-strange resonance at 2.32 GeV/c suggests a possible multiquark state. Three types of multiquark bound states are reviewed. A previous model-independent variational approach considers a tetraquark with two heavy…
We propose stable exotic nuclei bound with $\bar{D}$ and $B$ mesons with respecting heavy quark symmetry. We indicate that an approximate degeneracy of $\bar{D}$($B$) and $\bar{D}^{*}$($B^{*}$) mesons plays an important role, and discuss…
The recently developed method to investigate mesonic fluctuations off the chiral soliton in the Nambu--Jona--Lasinio model is applied to kaons in the S--wave channel. It is shown that for commonly accepted choices of parameters the presence…
Using the one-boson-exchange model, we investigate the interactions between the doubly charmed baryon $\Xi_{cc}(3621)$ and the $S-$wave (anti-)kaon accounting for the $S-D$ wave mixing and coupled-channel effects. We find the coupled…
A systematic study of the electromagnetic properties of exotic states is conducted to elucidate their nature, which continues to be the subject of controversy and incomplete understanding in the field. In this study, the magnetic dipole and…
Despite the apparent simplicity of meson spectroscopy there are some states which cannot be accommodated in the usual $q\bar q$ structure. Among them there are either exotic states as the X(1600), or the recently measured charmed states…
We estimate the mass of the pentaquark state with QCD sum rules and find that pentaquark states with isospin $I=0, 1, 2$ lie close to each other around $(1.55\pm 0.15)$ GeV. The experimentally observed baryon resonance $\Theta^+ (1540)$…
In the framework of the improved chromomagnetic interaction model, we complete a systematic study of the $S$-wave tetraquark states $Qq\bar{Q}\bar{q}$ ($Q=c,b$, and $q=u,d,s$) with different quantum numbers, $J^{PC}=0^{+(+)}$, $1^{+(\pm)}$,…
Within the framework of QCD sum rules, we have investigated the tetraquark states with three heavy quarks. We systematically construct the interpolating currents for the possible $cc\bar{c}\bar{q}$, $cc\bar{b}\bar{q}$, $bc\bar{b}\bar{q}$,…
We perform a systematical investigation of the doubly charmed dibaryon system with quantum numbers $IJ=01$, and strangeness numbers $S=0$, $-2$ and $-4$ in the framework of the chiral quark model. Two resonance states with strangeness…
Treating the $X(4140)$ as a compact $J^{PC}=1^{++}$ $cs\bar{c}\bar{s}$ state and using its mass as a reference scale, we systematically estimate the masses of doubly heavy tetraquark states $QQ\bar{q}\bar{q}$ where $Q=c,b$ and $q=u,d,s$.…