Related papers: New hadron configuration: The double-gluon hybrid …

We revisit the masses of heavy quarkonium double-gluon hybrid mesons with exotic quantum numbers $J^{PC}=1^{-+}$ and $2^{+-}$ in the framework of the QCD sum rules. Considering the double-gluon hybrid meson operators in the octet-octet…

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 exotic J^{PC}= 1^{-+} resonance {\pi}_{1}(1600)is examined in the framework of the Quark Model with Constituent Gluon (QMCG). We report the possibility of interpreting that resonance as quark-antiquark-gluon hybrid meson, with a masse =…

We investigate the heavy quarkonium hybrid mesons with exotic quantum numbers $J^{PC}=2^{+-}$ via QCD sum rule method. We construct the currents with three Lorentz indices and calculate the correlation functions up to dimension six at the…

I review some selected aspects of the phenomenology of multiquark states discovered in high energy experiments. They have four valence quarks (called tetraquarks) and two of them are found to have five valence quarks (called pentaquarks),…

In this work, we study the $1^{--}$ double-gluon charmonium ($\bar{c}ggc$) and bottomonium ($\bar{b} gg b$) hybrids in terms of QCD sum rules. We find that the mass of $\bar{c}ggc$ hybrid lies in $M_{H_{c}}$ = $5.33 \sim 5.90$ GeV, while in…

Using the method of QCD Sum Rules we estimate the energy of lowest energy top quark meson state with a hybrid admixture. This new estimate uses the previous estimates of hybrid charmonium and upsilon states, but with the mass of the top…

We investigate charmed hybrid baryons using the QCD sum rule method within the framework of heavy quark effective theory. We construct twenty-eight interpolating currents for charmed hybrid baryons, seven of which are employed in QCD sum…

The Abelian decomposition of QCD which decomposes the gluons to the color neutral binding gluons and the colored valence gluons shows that QCD can be viewed as the restricted QCD (RCD) made of the binding gluons which has the valence gluons…

We investigate the light quarkonium hybrid mesons of various spin-parities in QCD. Considering different interpolating currents made of the valence light quarks and single gluon, we calculate the mass and current coupling of the strange and…

We discriminate gluonic hadrons from conventional $q\bar q$ states by surveying radial and orbital excitations of all I=0 and I=1 $n\bar n$ systems anticipated up to 2.1 GeV. We give detailed predictions of their quasi-two-body branching…

QCD permits the existence of hybrid mesons that are made up of both quarks and gluons, including exotic states, i.e., quantum numbers prohibited for pure quark-antiquark states, with possible candidates found in experiments. We present…

We study the possible interpretation of the two exotic resonances $J^{PC}= 1^{-+}$ at 1400 and 1600 MeV, claimed to be observed by BNL, decaying respectively into $\eta\pi$, $\eta'\pi$, $f_{1}\pi$ and $\rho\pi$. These objects are…

QCD-motivated models for hadrons predict an assortment of "exotic" hadrons that have structures that are more complex than the quark-antiquark mesons and three-quark baryons of the original quark-parton model. These include pentaquark…

QCD theory allows the existence of states which cannot be built by the naive quark model; both theoretical arguments and experimental data confirm the hypothesis that gluons may have freedom degrees at the constituent level, and should be…

A unique feature of quantum chromodynamics (QCD), the theory of strong interactions, is the possibility for gluonic degrees of freedom to participate in the construction of physical hadrons, which are color singlets, in an analogous manner…

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…

Hadron spectroscopy has received revitalised interest due to the discovery of states with unexpected properties. Discussed are the recent findings at BABAR, CLEO, BELLE and BES. A detailed report is given on the many experiments reporting…

Hybrid (exotic) mesons, which are important predictions of quantum chromodynamics (QCD), are states of quarks and anti-quarks bound by excited gluons. First principle lattice study of such states would help us understand the role of…

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…