In this article, we tentatively assign the X∗(3860) to be the Cγ5 ⊗ γ5C type scalar tetraquark state, study its mass and width with the QCD sum rules, special attention is paid to calculating the hadronic coupling constants GXηcπ and GXDD concerning the tetraquark state. We obtain the values MX = 3.86±0.09GeV and ΓX = 202MeV with large uncertainty, which are consistent with the experimental dat...

Highlights in the search for nonconventional (non qq̄) meson states are the π1(1400) and π1(1600) exotic candidates. Should they exist, mounting theoretical arguments suggest that they are tetraquark molecular resonances excitable by meson rescattering. We report a new tetraquark calculation within a model field theory approximation to Quantum Chromodynamics in the Coulomb gauge supporting this ...

In this article, we take the point of view that there exists a hidden charmed tetraquark state with spin-parity J = 1, and calculate its mass with the QCD sum rules. The numerical result indicates that the mass of the vector hidden charmed tetraquark state is about MZ = (4.22 ± 0.10)GeV, which is consistent with the experimental data on the πχc1 invariant mass distribution. The hidden charmed m...

The decays of a light scalar meson into a vector meson and a photon (S → V γ) are evaluated in the tetraquark and quarkonium assignments of the scalar states. A link with the radiative decays φ → Sγ is established: experimental results for S → V γ will allow to understand if the direct, quark-loop contribution to φ→ Sγ or the kaon-loop contribution is dominant. Also strong decays S → PP -where ...

In this article, we assume that the mesons in the πχc1 invariant mass distribution are scalar hidden charmed tetraquark states and calculate their masses with the QCD sum rules. The numerical result indicates that the masses are about MZ = (4.48 ± 0.12)GeV. In previous work, we observe that the masses of the vector hidden charmed tetraquark states are about MZ = (4.81±0.11)GeV or MZ = (4.83±0.1...

Considering four-point correlation functions of color-singlet quark bilinears, we investigate, in the largeNc limit of QCD, the subleading diagrams that involve, in the s-channel of meson–meson scattering amplitudes, two-quark–two-antiquark intermediate states. The latter contribute, together with gluon exchanges, to the formation, at the hadronic level, of two-meson and tetraquark intermediate...

In this letter, we take the point of view that the X(1576) be tetraquark state which consists of a scalar-diquark and an anti-scalar-diquark in relative P -wave, and calculate its mass in the framework of the QCD sum rules approach. The numerical value of the mass mX = (1.66±0.14)GeV is consistent with the experimental data, there may be some tetraquark component in the vector meson X(1576). PA...

The recently observed Y(4260) lies far above the decay threshold with a width less than 100 MeV. We argue that it’s very difficult to accommodate Y(4260) as a conventional cc̄ radial excitation or a D-wave state. It can’t be a hadronic molecule. Its special decay pattern does not favor the glueball interpretation. If Y(4260) is a scalar tetraquark, it must be produced by the I = 0 component of t...

Very recently, the DØ Collaboration observed a narrow structure by analyzing the Bsπ ± invariant mass spectrum, which was named as the X(5568) [1]. The X(5568) has a mass m = 5567.8 ± 2.9(stat)+0.9 −1.9(syst) MeV and width Γ = 21.9 ± 6.4(stat)+5.0 −2.5(syst) MeV [1]. Its discovery mode indicates that the valence quark component of the X(5568) should be lsl̄b̄ (l = u or d). Thus, the X(5568) is a ...

The Babar, Belle, CLEO, D0, CDF and FOCUS collaborations have discovered (or confirmed) a large number of charmonium-like states X(3940), X(3872), Y (4260), Y (4008), Y (3940), Y (4325), Y (4360), Y (4660), etc, and revitalized the interest in the spectroscopy of the charmonium states [1, 2, 3, 4]. Many possible assignments for those states have been suggested, such as multiquark states (whethe...