Related papers: Sigma meson in pole-dominated QCD sum rules

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…

In this article, we take the point of view that Y(2175) be a tetraquark state which consists of color octet constituents, and calculate its mass and decay constant within the framework of the QCD sum rule approach. We release standard…

The fully heavy axial-vector diquark-antidiquark structures $bb\overline{c} \overline{c}$ are explored by means of the QCD sum rule method. They are modeled as four-quark mesons $T_{\mathrm{1}}$ and $T_{\mathrm{2}}$ composed of…

In this article, we take the point of view that the $0^{++}$ nonet mesons below $1 GeV$ are diquark-antidiquark states $(qq)_{\bar{3}}(\bar{q}\bar{q})_3$, and devote to determine their masses in the framework of the QCD sum rules approach…

In the framework of an extended chromomagnetic model, we systematically study the mass spectrum of the $S$-wave $qQ\bar{Q}\bar{Q}$ tetraquarks. Their mass spectra are mainly determined by the color interaction. For the $qc\bar{c}\bar{c}$,…

Exotic penta-quark baryon with strangeness +1, \Theta^+, is studied in the QCD sum rule approach. We derive sum rules for the positive and negative parity baryon states with J=1/2 and I=0. It is found that the standard values of the QCD…

We study the dynamical generation of scalar mesons in the light quark sector ($q\in\{u,d,s\}$) and calculate the masses and widths for the $f_0(500),a_0(980)$ and $f_0(980)$. To this end we study the mixing of conventional $q\bar{q}$ and…

We elaborate masses of open-charm mesons (c\bar{d} and c\bar{s}) with J^P=0^-,1^-,0^+,1^+ from a viewpoint of ordinary light-heavy systems in the analysis of standard Borel-transformed QCD sum rule. This analysis is implemented with the…

The analysis of the sum rules (for two differentchoices of 5-quark currents) indicate that to explain experimental results it is necessary to have some one-particle lower state (and pentaquark is a reliable candidate to this state) while…

The available data on the a0(980), f0(980), f0(1300) and K*0(1430) mesons are fitted as a distorted 0++ nonet using only 6 parameters and a very general model. This includes all light two-pseudoscalar thresholds, constraints from Adler…

According to a recent proposal of the tetraquark mixing framework, the two light-meson nonets in the $J^{P}=0^{+}$ channel, namely the light nonet composed of $a_0 (980)$, $K_0^* (800)$, $f_0 (500)$, $f_0(980)$, and the heavy nonet of $a_0…

In this article, we study the axialvector-diquark-scalar-diquark-antiquark type charmed pentaquark states with $J^P={\frac{3}{2}}^\pm$ with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of…

Recently, the BESIII Collaboration indicate that no $\Lambda_c\bar{\Sigma}_c$ bound-state with a mass near threshold in the range $4715$--$4735~\mathrm{MeV}$ was observed. In order to determine the plausible mass region of the states in…

We embark on systematic explorations of the behaviour of tetraquark mesons (colour-singlet bound states of two quarks and two antiquarks) in the (idealized) limit of a large number $N_c$ of colour degrees of freedom of quantum…

We apply the method of QCD sum rules to study the $s s \bar s \bar s$ tetraquark states of $J^{PC} = 0^{-+}$. We construct all the relevant $s s \bar s \bar s$ tetraquark currents, and find that there are only two independent ones. We use…

We study the tetraquark state with I^G J^{PC} = 0^+ 1^{-+} in the QCD sum rule. We exhaust all possible flavor structures by using a diquark-antidiquark construction and find that the flavor structure 3*6+6*3 is preferred. There are…

We discuss the mass splittings for the $S$-wave triply heavy pentaquark states with the $QQQq\bar{q}$ $(Q=b,c;q=u,d,s)$ configuration which is a mirror structure of $Q\bar{Q}qqq$. The latter configuration is related with the nature of…

We estimate the masses of the 1^{--} heavy four-quark and molecule states by combining exponential Laplace (LSR) and finite energy (FESR) sum rules known perturbatively to lowest order (LO) in alpha_s but including non-perturbative terms up…

We review our results in Refs.[1,2] for the masses and couplings of heavy-light DD(BB)-like molecules and (Qq)(Qq)-like four-quark states from relativistic QCD Laplace sum rules (LSR) where next-to-next-to-leading order (N2LO) PT…

In this paper, we have systematically explored the mass spectrum of fully strange tetraquark candidates within the framework of QCD sum rules, focusing on states with quantum numbers $J^{PC}=0^{++}$, $0^{-+}$, $0^{--}$, $1^{--}$, $1^{+-}$,…