Related papers: A possible global group structure for exotic state…
Recent lattice QCD results on the hadron spectroscopy with beauty and charm quarks is reviewed. The focus of the review are exotic hadrons, while non-lattice approaches and conventional hadrons are reported as well. We discuss the recently…
The pentaquark state recently discovered has been discussed based on various quark model calculations. Odd parity for the state can not be ruled out theoretically because contributions related to non-trivial color structures have not been…
Multiquark systems such as tetraquarks, pentaquarks and hexaquarks states are studied as di-hadronic molecules in a nonrelativistic model. The masses of several di-hadronic states using a molecular interaction provided by asymptotic…
Inspired by the fully heavy tetraquark states reported by the LHCb, ATLAS and CMS Collaborations, we perform a systemical investigation of the low-lying fully heavy pentaquark systems composed of charm and bottom quarks (anti-quark) in the…
The discovery of XYZ exotic states in the hadronic sector with two heavy quarks constitute one of the most important open problems in particle theory. In this work, we demonstrate that the QCD derived Born-Oppenheimer effective field theory…
We present quantitative results for masses and the internal structure of four-quark states with two heavy quarks, i.e. $QQ'\bar{q}\bar{q}'$ with $Q,Q'\in \{c,b\}$ and $q,q' \in \{u,d,s\}$, and $J^{P} \in {1^+}$. The composition of these…
We present an exact method based on a hyperspherical harmonic expansion to study systems made of quarks and antiquarks of the same flavor. Our formalism reproduces and improves the results obtained with variational approaches. This analysis…
This is the second of two companion papers in which we continue to develop the construction of the doubly heavy pentaquark systems using the gauge/string duality. In this paper, we propose a stringy description of the $Q\bar Qqqq$ system in…
We present an exact method to study four-quark systems based on the hyperspherical harmonics formalism. We apply it to several physical systems of interest containing two heavy and two light quarks using different quark-quark potentials.…
Investigating the electromagnetic characteristics of unconventional states may offer new insights into their internal structures. In particular, the magnetic moment attributes may serve as a crucial physical observable for differentiating…
The H1 and ZEUS collaborations have recently reported a significant excess of events at high $Q^2$ in positron-proton collisions. While there exists insufficient data to conclusively determine the origin of this excess, one possibility is…
In this proceedings we consider several states, namely the $D^*_{s0}(2317)$, $D_{s1}(2460)$, $D^*_{0}(2300)$ and $D_{1}(2430)$, which appear to defy description as simple quark-antiquark pairs. Theoretical input from unitarized chiral…
The newly observed $\Theta^+$ resonance is believed to be a pentaquark with the constituent quarks $uudd\bar s$. There are a few options for the constituent quark structure. Some advocate diquark-diquark-antiquark $(ud)$-$(ud)$-$\bar s$…
The LHCb collaboration reported a fully charmed tetraquark state X(6900) in the invariant mass spectrum of $J/\psi$ pairs in 2020. This discovery inspires us to further study the fully heavy pentaquark system. In this work, we investigate…
We study the tetraquark states with I^G J^{PC}=1^- 1^{-+} in the QCD sum rule. After exhausting all possible flavor structures, we analyses both the SVZ and finite energy sum rules. Both approaches lead to a mass around 1.6 GeV for the…
We predict several new exotic doubly-heavy hadronic resonances, inferring from the observed exotic bottomonium-like and charmonium-like narrow states $X(3872)$, $Z_b(10610)$, $Z_b(10650)$, $Z_c(3900)$, and $Z_c(4020/4025)$. We interpret the…
In the past few years the field of hadron spectroscopy has seen renewed interest due to the pubblication, initially mostly from B-Factories, of evidences of states that do not match regular spectroscopy, but are rather candidates for bound…
The possibility for a common effective field theory for hadronic molecules with different heavy-quark flavours is examined critically. It is argued that such a theory does not allow one to draw definite conclusions for doubly heavy…
Exotic hadrons are a new class of hadronic states whose properties do not allow them to be classified as conventional quark-antiquark mesons or three quark baryons. Finding new and understanding established exotic states is the most…
We present a generalization of the hyperspherical harmonic formalism to study systems made of quarks and antiquarks of the same flavor. This generalization is based on the symmetrization of the $N-$body wave function with respect to the…