Related papers: Comment on the X(3915) nonstandard hadron candidat…

The P-wave charm-strange mesons $D_{s0}(2317)$ and $D_{s1}(2460)$ lie below the $DK$ and $D^\ast K$ threshold respectively. They are extremely narrow because their strong decays violate the isospin symmetry. We study the possible heavy…

In this paper, we study double charmonia production in Upsilon peaks, especially, a S-wave charmonium $\eta_c$ and a P-wave charmonium $h_c(^1P_1)$, or a S-wave charmonium $J/\psi$ and the $X(3940)$ and $X(4160)$ within the nonrelativistic…

It is suggested that the resonance $\psi(3770)$ may contain a sizeable ($O(10%)$ in terms of the probability weight factor) four-quark component with the up- and down- quarks and antiquarks in addition to the $c {\bar c}$ pair, which…

Despite being extensively studied since their initial discovery in 2003, the XYZ states do not yet have a clear interpretation. BESIII recently collected additional data above 4 GeV which can be used to further study these exotic hadron…

Nonleptonic $B$ to charmonium decays generally deviate from the factorization predictions. We study rescattering effects mediated by intermediate charmed mesons in this class of decay modes and, in particular, we consider $B^- \to K^- h_c$…

I discuss the nature of the new charm and charmonium like states observed in the last few years and measurements that can test these assignments. In particular it appears that the X(3943) is the eta_c''(3^1S_0) which can be tested by…

We present recent results in semileptonic and non-leptonic exclusive $B_c$ decays to charmonium states both in $S$-wave, $J/\psi$ and $\eta_c$, and in $P$-wave, $\chi_{cJ}$ and $h_c$. The analysis, based on the heavy quark spin symmetry…

We report on further evidence that the Y(3940) and the recently observed Y(4140) are heavy hadron molecule states with quantum numbers J(PC) = 0(++). The Y(3940) state is considered to be a superposition of D*(+)D*(-) and D*(0) barD*(0),…

Contrary to almost standard opinion that the X(3872) resonance is the D^{*0}\bar D^0+c.c. molecule or the qc\bar q\bar c four-quark state, we discuss the scenario where the X(3872)resonance is the c\bar c = \chi_{c1}(2P) charmonium which…

Using the QCD sum rule approach we study the X(4260) state assuming that it can be described by a mixed charmonium-tetraquark current with $J^{PC}=1^{--}$ quantum numbers. For the mixing angle around $\theta=(53.0 \pm 0.5)^0$, we obtain a…

We predict several new exotic doubly-heavy hadronic resonances, inferring from the observed exotic bottomonium-like and charmonium-like narrow states $X(3872)$, $Z_b(10610)$, $Z_b(10650)$, $Z_c(3900)$, and $Z_c(4020/4025)$. We interpret the…

The exclusive rare radiative B meson decay to the orbitally excited tensor K_2^*(1430) meson is investigated in the framework of the relativistic quark model based on the quasipotential approach in quantum field theory. The calculated…

It has been proposed that the recently discovered archetypical "exotic" meson, X(3872), with M(X(3872))=3871.68+-0.17 MeV/c^2, and an extremely narrow width, Gamma(X(3872))<1.2 MeV, is a hadronic molecule of bound D^0 and D^*0 mesons. If…

The BABAR Collaboration performed a search for xi(2220) production in the initial-state radiation process e^+e^- --> gamma J/psi, J/psi --> gamma K^+K^- or J/psi --> gamma K^0_SK^0_S. No evidence for the xi(2220) resonance has been found.…

$R$ measurement data taken with the BESII detector at center-of-mass energies between 3.7 and 5.0 GeV is fitted to determine resonance parameters (mass, total width, electron width) of the high mass charmonium states, $\psi(3770)$,…

Based on the data samples collected at the energies of $J/\psi$, $\psi(3686)$, $\psi(3770)$ and $\psi(4040)$ resonances with the BESIII detector at the BEPCII storage ring, we present charmonium decays in two aspects. One is the search for…

The low mass of the $\Lambda(1405)$ hyperon with $j^P = 1/2^-$, which is higher than the ground state $\Lambda(1116)$ mass by 290 MeV, is difficult to understand in quark models. We analyze the hyperon spectrum in the bound state approach…

We investigate theoretical interpretations of the 1.4 GeV J^PC exotic resonance reported by the E852 collaboration. It is argued that interpretation in terms of a hybrid meson is untenable. A K-matrix analysis shows that the 1.4 GeV…

Three neutral resonances $\Xi_c(2923)^0$, $\Xi_c(2939)^0$ and $\Xi_c(2965)^0$ have been observed in the $\Lambda_c^+ K^-$ mass spectrum by the LHCb Collaboration. Given the $\Xi_c$ and $\Xi_c^\prime$ mass spectra predicted by the…

Mass spectra and decay properties of the low-lying orbital excited $\Xi_c^{(\prime)}$ baryons are investigated in the framework of the chiral quark model and quark pair creation mechanism, which are mainly based on the recently experimental…