Related papers: Multiquark-Oriented QCD Sum Rules
In this article, we extend our previous work to study the mass spectrum of the ground state hidden-bottom tetraquark states with the QCD sum rules in a systematic way. The predicted hidden-bottom tetraquark masses can be confronted to the…
Four-quark states with different internal clusters are discussed within the constituent quark model. It is pointed out that the diquark concept is not meaningful in the construction of a tetraquark interpolating current in the QCD sum rule…
We study pentaquark $\Theta^{+} (I=0,J=1/2)$ in the QCD sum rules emphasizing that we can not extract any properties of the pentaquark outside of the Borel window. To find the appropriate Borel window, we prepare a favorable set up of the…
We apply the method of QCD sum rules to study the \(QQ\bar{Q}\bar{q}\) and \(QQ\bar{Q}\bar{s}\) tetraquark states, where $Q=c,b$ and $q=u,d$, with the quantum number \(J^P = 0^{+}\). We consider the contributions of vacuum condensates up to…
We investigate three possible pentaquark candidates, one of which contains a single charm quark and the other two contain triple charm quarks in their substructure. To this end we apply QCD sum rule method and take into account both the…
Spectrum of the low-lying hidden- and double-charm tetraquark states are investigated in a nonrelativistic quark potential model, where the Instanton-induced interaction is taken as the residual spin-dependent hyperfine interaction between…
The QCD sum rule technique is employed to investigate pentaquark states with strangeness S = +1 and IJ^P = 0,1/2^\pm, 1,1/2^\pm, 0,3/2^\pm, 1,3/2^\pm. Throughout the calculation, emphasis is laid on the establishment of a valid Borel…
We propose a phenomenological QCD sum rule with an explicit diquark field to investigate the essential ingredients inside the hadrons. Introducing the mass (m_\phi) and the condensate (\phi^2) for the diquark field as parameters in the…
The external-field method has been used extensively in the QCD sum-rule approach to explore various hadron static properties. In the traditional formalism of this method, the transitions from the ground state hadron to excited states are…
We study tetraquarks in large $N$ QCD with heavy quarks, in the domain where non-relativistic quantum mechanics offers an adequate approximation. Within the regime of validity of the Born-Oppenheimer approximation, we systematically study…
A new color basis system and confinement mechanism for multi-quark systems are proposed according to the string-type picture of QCD. The color string configurations in the strong coupling QCD are implemented in the set of color basis…
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 this article, we perform a systematic study of the mass spectrum of the scalar doubly charmed and doubly bottom tetraquark states using the QCD sum rules.
I review here the most recent results about the observation and the study of hadronic bound states that do not fit well in the standard quarkonium picture. Several new states have been observed in the last few years, at B-, tau-Factories…
In this paper, we study the scalar triple-heavy tetraquark states with quark content $cc\bar{c}\bar{s}$, $\eta_{c}D_{s}$ molecular state and $[cc]_{A(T)}[\bar{c}\bar{s}]_{A(T)}$ compact tetraquark states, by the QCD sum rule method. First,…
Scores of exotic hadrons, particularly tetraquarks and pentaquarks in the heavy-quark sector, have been observed in the past 20 years, and more continue to be discovered to this day. Unlike mesons and baryons, such exotics are not mandated…
We analyse the extraction of the bound-state form factor from vacuum-to-hadron correlator, which is the basic object for the calculation of hadron form factors in the method of light-cone sum rules in QCD. We study this correlator in…
We review the exotic states, such as the $X$, $Y$, $Z$, $T$ and $P$ states, and present their possible assignments based on the QCD sum rules. We present many predictions which can be confronted to the experimental data in the future to…
This talk reviews the recent progress in the extraction of bound-state characteristics from the operator-product expansion (OPE) for field-theory correlators, which constitutes the basis of the method of QCD sum rules. This progress is…
In these lectures, I present several important applications of QCD sum rules to the decay processes involving heavy-flavour hadrons. The first lecture is introductory. As a study case, the sum rules for decay constants of the heavy-light…