Related papers: The $X(6900)$ peak could be a molecular state
In this work, we study the strong decay of the newly observed $P_{cs}(4459)$ assuming that it is a pure $\Xi_c\bar{D}^{*}$ molecular state. Considering two possible spin-parity assignments $J^P=1/2^{-}$ and $J^P=3/2^{-}$ the partial decay…
The unusual properties of the X(3872) have led to speculation that it is a weakly bound state of mesons, chiefly $D^0\bar D^{0*}$. Tests of this hypothesis are investigated and it is proposed that measuring the $3\pi J/\psi$, $\gamma…
Recent re-analyses of the di-$J/\Psi$ invariant mass spectra reveal a state near the di-$J/\Psi$ threshold, referred to as the $X(6200)$. Yet the nature of this near-threshold pole--whether it is a resonant, bound, or virtual state--remains…
We perform a systematical study of possible molecular states composed of the $S$ wave heavy light mesons, where the $S-D$ mixing and {$\eta-\eta^{\prime}$ mixing} are explicitly included. Our calculation indicates that the observed…
Recently, the LHCb Collaboration reported a new structure $P_{cs}(4459)$ with a mass of 19 MeV below the $\Xi_c \bar{D}^{*} $ threshold. It may be a candidate of molecular state from the $\Xi_c \bar{D}^{*} $ interaction. In the current…
The strong and electromagnetic decays of $X(4350)$ with quantum numbers $J^P =0^{++}$ and $2^{++}$ have been studied by using the effective Lagrangian approach. The coupling constant between $X(4350)$ and $D_s^{\ast}D_{s0}^{\ast}$ is…
We consider how the recent CMS measurements of the masses and quantum numbers of $X(6600)$, $X(6900)$ and $X(7100)$ can help to reveal the internal structure of these apparent $cc\bar{c}\bar{c}$ tetraquark states. The measured $J^{PC} =…
The LHCb Collaboration recently observed new structures in the invariant mass spectrum of $J/\psi J/\psi$ meson pairs produced in proton-proton collisions, including a narrow peak around $6.2$ GeV. This study investigates the thermal…
The 2020 announcement by LHCb of a narrow structure $X(6900)$ in the di-$J/\psi$ spectrum -- a potential $c\bar c c\bar c$ state -- has opened a new era in hadronic spectroscopy. In this talk, we briefly survey theory works preceding this…
We search, for the first time, for an exotic molecular state with quantum numbers $J^{PC}=1^{-+}$, called $X$, via the process $e^{+}e^{-} \to \gamma D^{+}_{s} D_{s1}^{-}(2536) +c.c.$ using data samples corresponding to a luminosity of…
A comprehensive study on the nature of the $Z_c(3900)$ resonant structure is carried out in this work. By constructing the pertinent effective Lagrangians and considering the important final-state-interaction effects, we first give a…
The LHCb Collaboration has recently discovered a structure around 6.9 GeV in the double-$J/\psi$ mass distribution, possibly a first fully-charmed tetraquark state $X(6900)$. Based on vector-meson dominance (VMD) such a state should have a…
The hadronic tensor molecule $\mathcal{M}=J/\psi J/\psi$ is investigated in the framework of QCD sum rule method. We evaluate its mass and current coupling using the two-point SR approach. Our result $m=(6290 \pm 50)~ \mathrm{MeV}$ for the…
Very recently the LHCb Collaboration reported their observation of the first two fully open-flavor tetraquark states, the $X_0(2900)$ of $J^P = 0^+$ and the $X_1(2900)$ of $J^P = 1^-$. We study their possible interpretations using the…
Inspired by the $X(4140)$ structure reported in the $J/\psi \phi$ system by the CDF experiment in 2009, a series of searches have been carried out in the $J/\psi \phi$ and $J/\psi K$ channels, leading to the claim of ten structures in the…
The $X(3872)$ could be a shallow $D\bar D^*$ bound state, a compact four-quark state, or a partially composite particle, i.e. a superposition of the two. We will review how these hypotheses could be tested experimentally, examining…
We show that a $\Xi ^{\ast}$ pole can be dynamically generated near the $\bar{K} \Sigma$ threshold as an $s$-wave $\bar{K} \Sigma$ molecular state in a coupled-channels unitary approach with the leading-order chiral interaction. This $\Xi…
Recently, the LHCb Collaboration has reported two strange hidden-charm pentaquark states named $P^\Lambda_{\psi s}(4459)$ and $P^\Lambda_{\psi s}(4338)$ in the $ J/\psi \Lambda$ invariant mass spectra of decays $\Xi_b^-$$\to$$ J/\psi…
We study the $J/\psi \pi$ and $D\bar{D}^*$ coupled-channel system within a covariant framework. The $J/\psi \pi$ and $D\bar{D}^*$ invariant-mass distributions measured at 4.23~GeV and 4.26~GeV by BESIII and the finite-volume energy levels…
By using a combined amplitude analysis of the $\gamma\gamma\rightarrow D\bar{D}$ and $\gamma\gamma\rightarrow J/\psi\omega$ data, we demonstrate that the $X(3915)$, which is quoted as a $J^{PC}=0^{++}$ state in the Particle Data Group…