Related papers: Light Scalar Tetraquark Mesons in the QCD Sum Rule
In this article, we assume that there exists a scalar hidden charm tetraquark state in the $\pi^+ \chi_{c1}$ invariant mass distribution, and study its mass using the QCD sum rules. The numerical result $M_{Z}=(4.36\pm0.18) \rm{GeV}$ is…
In this work, we introduce an explicit P-wave to construct the diquarks $[qc]_{\widehat{V}}$, then construct the local four-quark currents to explore the hidden-charm tetraquark states with the $J^{PC}=0^{++}$, $1^{+-}$ and $2^{++}$ in the…
We use QCD sum rules to test the nature of the recently observed mesons Y(4260), Y(4350) and Y(4660), assumed to be exotic four-quark $(c\bar{c}q\bar{q})$ or $(c\bar{c}s\bar{s})$ states with $J^{PC}=1^{--}$. We work at leading order in…
Considering four-point correlation functions of color-singlet quark bilinears, we investigate, in the large-$N_{\mathrm{c}}$ limit of QCD, the subleading diagrams that involve, in the $s$-channel of meson-meson scattering amplitudes,…
In this article, we present the scalar-diquark-scalar-diquark-antiquark type and scalar-diquark-axialvector-diquark-antiquark type pentaquark configurations in the diquark model, and study the masses and pole residues of the…
We study the exotic $bc\bar{q}\bar{q}$, $bc\bar{s}\bar{s}$ and $qc\bar{q}\bar{b}$, $sc\bar{s}\bar{b}$ systems by constructing the corresponding tetraquark currents with $J^P=0^+$ and $1^+$. After investigating the two-point correlation…
Tetraquarks, bound states composed of two quarks and two antiquarks, have been the subject of intense study but are challenging to understand from first principles. We apply variational and Green's function Monte Carlo methods to compute…
The mass and coupling of the scalar tetraquark $T_{bb;\overline{u}\overline{d }}^{-}$ (hereafter $T_{b:\overline{d}}^{-} $) are calculated in the context of the QCD two-point sum rule method. In computations we take into account effects of…
We present a numerical solution of the four-quark Bethe-Salpeter equation for ground-state scalar tetraquarks with J^PC = 0^++. We find that the four-body equation dynamically generates pseudoscalar-meson poles in the Bethe-Salpeter…
We investigate f_0-sigma mixing in the framework of light cone QCD sum rules and by employing the experimental results about the decay widths and the masses of these scalar mesons we estimate the scalar mixing angle by using sigma meson…
The conjecture that several recently observed mesons have a structure, which is not dominated by an ordinary quark-antiquark pair, but by a four-quark structure, is being actively investigated both theoretical and experimentally. Such a…
We use the QCD sum rules to evaluate the mass of a possible scalar mesonic state that couples to a molecular $D_{s}^{*}\bar{D}_s^{*}$ current. We find a mass $m_{D_s^*D_s^*}=(4.14\pm 0.09)$ GeV, which is in a excellent agreement with the…
The strong decays of the pseudoscalar and scalar double-charmed tetraquarks $ T_{cc;\overline{u}\overline{d}}^{+}$ and $\widetilde{T}_{cc;\overline{u} \overline{d}}^{+}$ are investigated in the framework of the QCD sum rule method. The mass…
Using the QCD sum rules we test if the charmonium-like structure Y(4260), observed in the $J/\psi\pi\pi$ invariant mass spectrum, can be described with a $J/\psi f_0(980)$ molecular current with $J^{PC}=1^{--}$. We consider the…
It is suggested that the narrow meson state seen in the the SELEX experiment is a $(c\bar{s} s\bar{s})$ tetraquark state. Characteristics of other possible tetraquarks formed out of $c$ and $s$ quarks and antiquarks are considered.
In this article, we study the axial-vector tetraquark state and two-quark-tetraquark mixed state consist of light quarks using the QCD sum rules. The present predictions disfavor assigning the $a_1(1420)$ as the axial-vector tetraquark…
In "Landau equation and QCD sum rules for the tetraquark molecular states", I list out six reasons to refute the assertion of Lucha, Melikhov and Sazdjian. In "Comment on "Landau equation and QCD sum rules for the tetraquark molecular…
In this article, we construct the axialvector-diquark-scalar-diquark-antiquark type and the axialvector-diquark-axialvector-diquark-antiquark type interpolating currents, and study the $J^P={\frac{3}{2}}^\pm$ hidden-charm pentaquark states…
In this article, we take the $X(5568)$ as the diquark-antidiquark type tetraquark state with the spin-parity $J^P=0^+$, construct the scalar-diquark-scalar-antidiquark type current, carry out the operator product expansion up to the vacuum…
The concept of QCD sum rules is extended to bound states composed of particles with finite mass such as scalar quarks or strange quarks. It turns out that mass corrections become important in this context. The number of relevant corrections…