Related papers: Instanton induced quark dynamics and the pentaquar…
We consider the finite density, zero-temperature behaviour of quark matter in the instanton picture. Since the instanton-induced interactions are attractive in both $\bar{q}q$ and $qq$ channels, a competition ensues between phases of matter…
We analyze some aspects of the perturbative and non-perturbative interactions in the composition of heavy quarkonia, heavy and light baryons ($ccc$ and $uuu$ ones), as well as all charm tetraquarks ($cc\bar c\bar c$). Using the…
The strangeness $s=+1$ pentaquark states as $qqqq\bar{q}$ clusters are investigated in this letter. Starting from the inherent geometric symmetry, we analyzed the inherent nodal structure of the system. As the nodeless states, the low-lying…
The purported observation of a state $\Theta^+$ with strangeness S = +1 led to its quark model interpretation in terms of a pentaquark combination involving a triquark-diquark structure -- the Karliner-Lipkin model. In this work, the proper…
The present work reviews the various aspects of the extension of the large-$N_c$ approach, as had been proposed and developed by 't Hooft, to the case of tetraquark states, which are a category of the general class of exotic states, also…
In the framework of an extended chromomagnetic model, we systematically study the mass spectrum of the $S$-wave $qQ\bar{Q}\bar{Q}$ tetraquarks. Their mass spectra are mainly determined by the color interaction. For the $qc\bar{c}\bar{c}$,…
If Jaffe and Wilczek's diquark picture for $\Theta_5$ pentaquark is correct, there should also exist a $SU_F$(3) pentaquark octet and singlet with no orbital excitation between the diquark pair, hence $J^P={1/2}^-$. These states are lighter…
We determine the mass of tetraquark bound states from a coupled system of covariant Bethe-Salpeter equations. Similar in spirit to the quark-diquark model of the nucleon, we approximate the full four-body equation for the tetraquark by a…
Inspired by the $T^+_{cc}$ signal discovered by the LHCb Collaboration, we systematically investigate the doubly heavy tetraquark states with the molecule configuration $[Q_1\bar{q}_2][Q_3\bar{q}_4]$ ($Q=c$ and $b$, $q=u$, $d$ and $s$) in a…
Instantons generate strong non-perturbative interactions between quarks. In the vacuum, these interactions lead to chiral symmetry breaking and generate constituent quark masses on the order of 300-400 MeV. The observation that the same…
We study light quark interactions in the instanton liquid at finite quark/baryon number density analyzing chiral and diquark condensates and investigate the behaviors of quark dynamical mass and both condensates together with instanton…
Motivated by the discovery of several kaon-like states observed at BESIII and LHCb, this study explores S-wave and P-wave tetraquark states with quark contents $ss\bar{s}\bar{q}$ and $sq\bar{q}\bar{q}$ using potential-based phenomenology.…
Masses of heavy mesons, tetraquarks and pentaquarks computed in a potential model are shown. Tetraquarks are studied as bound states of a diquark and an antidiquark. Pentaquarks are constructed from a series of two-body interactions between…
We perform a theoretical study on the spectrum of the low-lying hidden-bottom ($q\bar{q}b\bar{b}$ with $q=$ $u$, $d$ and $s$) and double-bottom ($q\bar{q}bb$) tetraquark states within a nonrelativistic quark model, in which the…
In this article, we study the pentaquark state $ \Theta^+(1540)$ with a (scalar)diquark-(pseudoscalar)diquark-antiquark type interpolating current in the framework of the QCD sum rules approach by including the contributions from the direct…
An exotic narrow state in the $D^0D^0\pi^+$ mass spectrum just below the $D^{*+}D^0$ mass threshold is studied using a data set corresponding to an integrated luminosity of 9 fb$^{-1}$ acquired with the LHCb detector in proton-proton…
Thirty years ago we proposed string junction model of hadrons and examined structure and reaction of hadrons including exotic ones. Mass $m$ of exotic hadrons of light quarks is roughly given by $m \sim N_J\cdot m_B$, where $N_J$ is the…
The possibility of the existence of multiquark hadrons made of 4-quark for mesons and 5-quark for baryons was predicted by Gell-Mann in Ref. [1]. The renewed interest for the search of exotic pentaquark states was initiated by the paper by…
We systematically investigate the electromagnetic properties of exotic states whose internal structures remain uncertain and for which different models have been proposed. In this work, we focus on the magnetic dipole moments of…
We use lattice QCD to investigate the existence of strong-interaction-stable antiheavy-antiheavy-light-light tetraquarks. We study the $\bar b \bar b u s$ system with quantum numbers $J^P = 1^+$ as well as the $\bar b \bar c u d$ systems…