Related papers: XYZ: four-quark states?

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 review of recent experimental developments concerning the $X$, $Y$ and $Z$ charmonium-like exotic states.

The two exotic $P_c^+(4380)$ and $P_c^+(4450)$ discovered in $2015$ by the LHCb Collaboration, together with the four resonances $X(4140)$, $X(4274)$, $X(4500)$ and $X(4700)$, reported in $2016$ by the same collaboration, are described in a…

A study of resonant structures in $B^{+}\rightarrow{D^{\ast+}D^{-}K^{+}}$ and $B^{+}\rightarrow{D^{\ast-}D^{+}K^{+}}$ decays is performed, using proton-proton collision data at centre-of-mass energies of $\sqrt{s}=7, 8$, and $13$ TeV…

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…

Bound states of double-heavy tetraquarks are studied in a constituent quark model. Two bound states are found for isospin and spin-parity I(J^P ) = 0(1^+) in the bb\bar{u}\bar{d} channel. One is deeply bound and compact made of colored…

The beauty hadron decays is unique laboratory to study charmonium and charmonium-like states, such as the $\chi_{c1}(3872)$ meson, other exotic states and the tensor D-wave $\psi_2(3823$) states. However the nature of many exotic…

The LHCb Collaboration has recently observed two narrow baryon resonances with beauty. Their masses and decay modes look consistent with the quark model orbitally excited states Lambda_b(5912) and Lambda*_b(5920), with quantum numbers…

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 discuss the charge conjugation quantum number for tetraquarks or meson-meson molecules, seen as possible interpretations of the newly found $XYZ$ charmonium-like resonances.

We investigate the production of the fully - heavy tetraquark states $T_{4Q}$ in the $\gamma \gamma$ interactions present in proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN Large Hadron Collider (LHC). We focus on…

In the light of the recent discovery of the $\Xi^{++}_{cc}$ by LHCb collaboration, we study the stable doubly heavy tetraquarks. These states are compact exotic hadrons which can be approximated as the diquark-anti-diquark correlations. In…

The cross section for formation in $\gamma + p$ collisions of the recently found hidden-charm pentaquark states $P_c(4380)$ and $P_c(4450)$ is discussed and estimated. The studies of these resonances in photon beam experiments can be…

We study the possibility that four $\Xi$ resonances $(\Xi(1620)$, $\Xi(1690)$, $\Xi(1820)$, $\Xi(1950))$ could correspond to pentaquark states, in the form of meson-baryon bound systems. We also explore the possible existence of doubly…

The masses of the excited heavy tetraquarks with hidden charm are calculated within the relativistic diquark-antidiquark picture. The dynamics of the light quark in a heavy-light diquark is treated completely relativistically. The diquark…

We present a study of the low-lying $\Xi_{c/b}$ and $\Xi'_{c/b}$ baryon states based on masses, strong and radiative decays. In a harmonic oscillator quark model analysis it is found that the majority of the detected states can be…

We carry out a systematic study of exotic $QQ^\prime \bar q\bar q$ four-quark states containing distinguishable heavy flavors, $b$ and $c$. Different generic constituent models are explored in an attempt to extract general conclusions. The…

Observations of exotic structures in the $J/\psi p$ channel, that we refer to as pentaquark-charmonium states, in $\Lambda_b^0\to J/\psi K^- p$ decays are presented. The data sample corresponds to an integrated luminosity of 3/fb acquired…

We consider the recently suggested model for some resonances near the open charm threshold as bound states of charmonium inside excited light mesons. It is argued in the soft-wall holographic model of QCD that such states of heavy…

With new data sets, recently completed analyses and renewed interest, there has been significant progress in addressing existing questions about quarkonia production and decay ... but also new questions and new confrontation with theory.…