Related papers: $Z_c(4430)$ and $Z_c(4200)$ as triangle singularit…
The nature of the $P_{c}(4312)$, $P_c(4440)$ and $P_c(4457)$ pentaquarks is a fascinating theoretical question. Within the molecular picture their more usual interpretation is that of $I=\tfrac{1}{2}$ $\bar{D} \Sigma_c$ and $\bar{D}^*…
We identify the recently observed charmonium-like structure $Z_c^\pm(3900)$ as the charged partner of the X(3872) state. Using standard techniques of QCD sum rules, we evaluate the three-point function and extract the coupling constants of…
Hidden-charm pentaquarks were first experimentally detected by LHCb in 2019, one of which is the exotic $P_{c\bar{c}}(4312)^{+}$ state. The nature of this state remains uncertain which may be attributed to the proximity of this observed…
The LHCb collaboration has recently observed three narrow pentaquark states --- the $P_c(4312)$, $P_c(4440)$, and $P_c(4457)$ ---that are located close to the $\bar{D} \Sigma_c$ and $\bar{D}^* \Sigma_c$ thresholds. Among the so-far proposed…
We investigate the $Z_b$, $Z_c$ and $Z_{cs}$ states within the chiral effective field theory framework and the $S$-wave single channel molecule picture. With the complex scaling method, we accurately solve the Schr\"odinger equation in…
We compare contributions from the triangle diagram and the $D\bar D^*$ bubble chain to the processes of $e^{+}e^{-}\rightarrow J/\psi\pi^{+}\pi^{-}$ and $e^{+}e^{-}\rightarrow (D\bar D^*)^\mp\pi^{\pm}$. By fitting the $J/\psi\pi$ maximum…
Recent LHCb experiments have shown us that there are two resonances in the $J/\psi p$ channel in the $\Lambda_b$ decay, whose spin and parity are most probably (3/2$^-$ 5/2$^+$). In this work, we investigate the $I(J^P)=1/2(1/2^-)$,…
The masses of tetraquark states of all $qc\bar q \bar c$ and $cc\bar c \bar c$ quark configurations are evaluated in a constituent quark model, where the Cornell-like potential and one-gluon exchange spin-spin coupling are employed. All…
The recent experimental results of LHCb collaboration suggested the existence of pentaquark states with charmonium. To understand the structure of the states, a dynamical calculation of 5-quark systems with quantum numbers…
Assuming that the recently observed hidden-charm pentaquark state, $P_c(4450)$, is of molecular nature as predicted in the unitary approach, we propose to study the decay of $\Xi^-_b\rightarrow J/\psi K^- \Lambda$ to search for the…
The three pentaquark states, $P_{c}(4312)$, $P_{c}(4440)$, and $P_{c}(4457)$, discovered by the LHCb Collaboration in 2019, can be nicely arranged into a multiplet of $\bar{D}^{(\ast)}\Sigma_{c}^{(\ast)}$ of seven molecules dictated by…
Flavor-exotic tetraquark mesons have recently been observed in the heavy-quark pair sectors of QCD, including two isospin multiplets in the b b-bar sector, Z_b(10610) and Z_b(10650), and one isospin multiplet in the c c-bar sector,…
On March 26th, 2019, at the Rencontres de Moriond QCD conference, the LHCb Collaboration reported the observation of three new pentaquarks, namely $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$, which are consistent with the loosely bound…
Hidden-charm pentaquark-like $P_{\psi s}^\Lambda(4459)^0$ and $P_{\psi s}^\Lambda(4338)$ resonances are studied in a constituent quark model as molecular meson-baryon structures. Such states are found in the $J^P(I)=\frac{1}{2}^-(0)$…
Recently a novel hadronic state of mass 6.9 GeV, that decays mainly to a pair of charmonia, was observed in LHCb. The data also reveals a broader structure centered around 6490 MeV and suggests another unconfirmed resonance centered at…
In this article, we review the recent experimental studies on the charmoniumlike states, mainly from the e+e- annihilation experiments BESIII, Belle, BaBar, and CLEO-c, and the hadron collider experiment LHCb. We discuss the results on the…
One of the most intriguing puzzles in hadron spectroscopy are the numerous charmonium-like states observed in the last decade, including charged states that are manifestly exotic. The $BABAR$ and Belle experiments have extensively studied…
Studying exotic hadrons is a challenge against the conventional quark model, providing us with a good platform to deepen our understanding of the strong interaction. An inclusive study of the exotic hadrons in vacuum and at finite…
In light of the recently observed resonance states $P_{\psi s}^{\Lambda}(4338)^0$ and $P_{cs}(4459)^0$ by LHCb Collaboration in $J/\psi\Lambda$ decay channel, we perform a systematical study of all possible hidden-heavy pentaquarks with…
We review our results on $Z_{c}$-like states[1] which we complete with the ones on $Z_{b}$-like states by using relativistic QCD Laplace Sum Rules (LSR) within stability criteria and including Factorized Next-to-Leading Order (FNLO)…