Related papers: Light scalar mesons as tetraquarks within QCD Sum …
We present a QCD sum rule analysis for the anti-charmed pentaquark state with and without strangeness. While the sum rules for most of the currents are either non-convergent or dominated by the $DN$ continuum, the one for the non-strange…
Within the realm of QCD sum rules, one of the most important areas of application of this nonperturbative approach is the prediction of the decay constants of heavy mesons. However, in spite of the fact that, indisputably, the adopted…
In spite of undeniable similarities of the applied techniques, somewhat different challenges are encountered when extracting, from QCD sum rules derived from two-point correlators of appropriate interpolating heavy-light quark currents, the…
In this article, we study the mass spectrum of the scalar hidden charm and bottom tetraquark states with the QCD sum rules. The numerical results are compared with the corresponding ones from a relativistic quark model based on a…
The surprising thing is that arising almost 50 years ago from the linear sigma model (LSM) with spontaneously broken chiral symmetry, the light scalar meson problem has become central in the nonperturbative quantum chromodynamics (QCD) for…
Many of the $XYZ$ resonances observed by the Belle, Babar, CLEO and BESIII collaborations in the past decade are difficult to interpret as conventional quark-antiquark mesons, motivating the consideration of scenarios such as multi-quark…
We discuss a calculation of large-Nc masses of light scalar mesons from the QCD sum rules. Two methods based on the use of linear radial Regge trajectories are presented. We put a special emphasis on the appearance of pole near 0.5 GeV in…
In this talk, we briefly report the investigations of the mass spectra for the $cc\bar c\bar c, bb\bar b\bar b$, $bc\bar b\bar c$ and $cc\bar b\bar b$ tetraquark states by using the QCD moment sum rule method. The calculations for the…
In this paper we compute the decay constant of the pseudo-scalar heavy-light mesons in the heavy quark effective theory framework of QCD sum rules. In our analysis we include the recently evaluated three-loop result of order $\alpha_s^2$…
We study the mass of the state Y(2175) of J^{PC} = 1^{--} in the QCD sum rule. We construct both the diquark-antidiquark currents (ss)(s_bar s_bar) and the meson-meson currents (s_bar s)(s_bar s). We find that there are two independent…
We present a detailed study of a linear sigma model containing one chiral nonet transforming under U(1)$_A$ as a quark-antiquark composite and another chiral nonet transforming as a diquark-anti diquark composite (or, equivalently from a…
The nature of the recently observed $K(1690)$ state, reported by the COMPASS Collaboration as a candidate for a strange crypto-exotic meson with $J^P=0^-$, remains unclear. In this work, we investigate whether it can be described by local…
The surprising thing is that the light scalar meson problem, arising 50 years ago from the linear sigma model (LSM) with spontaneously broken chiral symmetry, has become central in the nonperturbative quantum chromodynamics (QCD), because…
We investigate the twist-3 light-cone distribution amplitudes (LCDAs) of the scalar mesons $a_0$, $K^{\ast}_0$ and $f_0$ within the QCD sum rules. The QCD sum rules are improved by a consistent treatment of the sizable $s$-quark mass…
In this article, we construct the axialvector-diquark-axialvector-antidiquark type tensor current to interpolate both the vector and axialvector tetraquark states, then calculate the contributions of the vacuum condensates up to…
The mass spectra of doubly heavy baryons are systematically calculated in the framework of QCD sum rules. With a tentative heavy-diquark--light-quark configuration, the interpolating currents representing the doubly heavy baryons are…
We consider a $[ud]^2\bar{s}$ current, in the finite-density QCD sum rule approach, to investigate the scalar and vector self-energies of the recently observed pentaquark state $\Theta^+(1540)$, propagating in nuclear mater. We find that,…
We derive the QCD sum rules for the vector and scalar meson mixing in nuclear medium, using a two quark interpolating field for both mesons. Modeling the mixing via a nucleon hole contribution with known coupling constant, the sum rule can…
The light scalar mesons below 1 GeV as tetraquark states are studied in the framework of the flux-tube model, the multi-body confinement instead of the additive two-body confinement is used. From the calculated results, we find that the…
We address the question whether the lightest scalar mesons sigma and kappa are tetraquarks, as is strongly supported by many phenomenological studies. We present a search for possible light tetraquark states with J^PC=0^++ and I=0, 1/2,…