Related papers: Tetraquarks in AdS/QCD
We give a review of the calculations of the masses of tetraquarks with two and four heavy quarks in the framework of the relativistic quark model based on the quasipotential approach and QCD. The diquark-antidiquark picture of heavy…
States beyond those expected in the simple constituent quark model are now emerging. I focus on the scalar glueball and its mixing with states in the $q\bar{q}$ nonet, and also on correlations in Strong QCD that may form diquarks and seed…
Hadrons, composed of quarks and gluons bound by Quantum Chromodynamics (QCD), traditionally classified as baryons (three quarks) and mesons (quark-antiquark pairs). Nothing in the theory of QCD stands against the existence of exotic hadrons…
Scalar mesons are a key expression of the strong coupling regime of QCD. How those with $I_3=0$ couple to two photons supplies important information about which is transiently ${\bar q}q$ or ${\bar {qq}} qq$ or multi-meson molecule or…
There are three $S$ and seven $P$ fully charmed $[cc][\bar c\bar c]$ tetraquarks, the mass spectrum from $1S$ to $2P$ excitations is calculated in a non-relativistic quark potential model. In the calculation, the interactions among four…
We consider a system composed of two identical light quarks ($qq$) and two identical antiquarks ($\bar Q\bar Q$) that can be linked either as two mesons or as a tetraquark, incorporating quantum correlations between identical particles and…
In this paper we explain and discuss some fundamental features of various models which are QCD-based and proposed to explain the hadron spectrum.
The vast majority of mesons can be understood as quark-antiquark states. Yet, various other possibilities exists: glueballs (bound-state of gluons), hybrids (quark-antiquark plus gluon), and four-quark states (either as diquark-antidiquark…
The typical AdS/QCD models deal with the large-N_c limit of QCD, as a consequence the meson spectrum consists of the infinite number of states that is far from the real situation. Basing on introduction of anharmonic corrections to the…
The role of quark correlations in the description of hadron dynamics in many domains of physics, from low energy dynamics to very hot(dense) systems, is being appreciated. Strong correlations of two quarks (diquark) have been widely…
Stimulated by the observation of the $X(6900)$ from LHCb in 2020 and the recent results from CMS and ATLAS in the di-$J/\psi$ invariant mass spectrum, in this work we systemically study all possible configurations for the ground fully heavy…
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 four-quark amplitudes of the tetraquarks with hidden…
A basic understanding of the relevant features of hadron properties from first principles QCD has remained elusive, and should be understood as emergent phenomena which depend critically on the number of dimensions of physical spacetime.…
Inspired by recent measurement of possible fully charmed tetraquarks in LHCb Collaboration, we investigate the mass spectra of fully heavy tetraquarks $QQ \bar Q \bar Q$ in an extended relativized quark model. Our estimations indicate that…
The dynamics of two heavy quarks inside the same hadron is probed against the double charm baryon results of SELEX. This can be seen as a part of the mechanism to bind tetraquarks with two heavy quarks and two light antiquarks. In the…
Spectral properties of hadrons in nuclear matter are treated in the framework of QCD sum rules. The influence of the ambient strongly interacting medium is encoded in various condensates. Especially, the structure of different four-quark…
The assumption of strong diquark correlations in the QCD spectrum suggests flavor multiplets of hadrons that are degenerate in the chiral limit. Generally it would be unnatural for there to be degeneracy in the hadron spectrum that is not…
We consider the production and decay of multiquark systems in the framework of string models where the hadron structure is determined by valence quarks together with string junctions. We show that the low mass multiquark resonances can be…
The nature of low-lying scalar and axial-vector charmed mesons has long been debated, specifically whether they are best explained as hadronic molecules or compact tetraquark systems. These two scenarios exhibit quite different features for…
The relativistic four-quark equations in the framework of the dispersion relation technique are derived. The four-quark amplitudes of the scalar tetraquarks with open bottom, including u, d, s and bottom quarks, are constructed. The poles…