Related papers: Does the $J^{PC}=1^{+-}$ counterpart of the $X(387…
The quantum numbers of the X(3872) meson are determined to be JPC = 1++ based on angular correlations in B+ to X(3872) K+ decays, where X(3872) to pi+pi- J/psi and J/psi to \mu+\mu-. The data correspond to 1.0 fb-1 of pp collisions…
The very recent analysis by BaBar Collaboration indicates that the $X(3872)$ may favor the quantum number $J^{PC}=2^{-+}$ rather than the previously assumed $1^{++}$. By pretending the $\eta_{c2}(1D)$ charmonium to be the $X(3872)$, we…
We present an analysis of angular distributions and correlations of the X(3872) particle in the exclusive decay mode X(3872)->J/psi pi+ pi- with J/psi->mu+ mu-. We use 780 pb -1 of data from ppbar collisions at sqrt{s} = 1.96 TeV collected…
The X(3872) with quantum numbers J(PC) = 1(++) is considered as a composite hadronic state comprised of the dominant molecular D(0) D*(0) component and other hadronic pairs - D(+-) D*(-+), Jpsi omega and Jpsi rho. Applying the compositeness…
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…
If the quantum numbers of the X(3872) are J^{PC}=1^{++}, the measurement of its mass implies that it is either a loosely-bound hadronic molecule whose constituents are a superposition of the charm mesons pairs D^{*0} Dbar^0 and D^0…
We explore the consequences of treating the X(3872) meson as a tetraquark bound state. As dynamical framework we employ a relativistic constituent quark model which includes infrared confinement in an effective way. We calculate the decay…
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…
Angular correlations in $B^+\to X(3872) K^+$ decays, with $X(3872)\to \rho^0 J/\psi$, $\rho^0\to\pi^+\pi^-$ and $J/\psi \to\mu^+\mu^-$, are used to measure orbital angular momentum contributions and to determine the $J^{PC}$ value of the…
Within the framework of the local hidden gauge approach, we have studied the near-threshold interaction of the $D^* \bar{D}^*$ channel with quantum numbers $I(J^{PC}) = 0(0^{++})$, $0(2^{++})$, $1(0^{++})$, and $1(2^{++})$, respectively.…
In this talk, we review our recent work about the dynamical studies of $Z^+(4430)$ and X(3872). $Z^+(4430)$ can not be explained as a $D_1'D^*$ or $D_1D^*$ molecular state only considering one pion exchange potential without the cutoff,…
In 2003 the X(3872) particle was discovered by the Belle collaboration. Despite results collected since then, the nature of the state still remains unclear. In this contribution we report on new results on properties of the X(3872) state…
The properties of the resonance X(3872) are discussed under the assumption that this resonance is dominantly a `molecular' $J^{PC}=1^{++}$ state of neutral $D$ and $D^*$ mesons. It is argued that in these properties should dominate the…
We discuss the possibility that the X(3872) can be a hadronic DD* bound state in the framework of a potential model. The potential is generated by the exchange of pseudoscalar, scalar and vector mesons resulting from the Lagrangian of heavy…
We analyze how the renowned X(3872), a weakly bound state right below the $D \bar D^*$ threshold, should effectively be included in a hadronic representation of the QCD partition function. This can be decided by analyzing the $D \bar D^*$…
It is pointed out that dipion invariant mass spectrum in $X (3872) \to \pi \pi J/\psi$ is a useful probe for the $J^{PC}$ quantum number of the X(3872), complementary to the angular distributions. If X(3872) is a $^1 P_1$ state, the dipion…
We perform a systematic study of the possible molecular states composed of a pair of heavy mesons such as $D\bar D$, $D^\ast\bar D$, $D^\ast \bar D^\ast$ in the framework of the meson exchange model. The exchanged mesons include the…
The lineshapes of specific production experiments of the exotic state such as $X(3872)$ with $J^{PC}=1^{++}$ quantum numbers involving triangle singularities have been found to become highly sensitive to the binding energy of weakly bound…
We present recent studies of charmonium multiquark states. We use different interacting models and numerical methods to study deeply bound four-quark states and meson-meson molecules. No deeply bound four-quark states are found in our…
The X(3872) and Y(4260), both discovered in $\pi^+\pi^- J/\psi$ mode, are rather unusual: $X_c\equiv X(3872)$ is very narrow, while $Y_c \equiv Y(4260)$ has large $Y_c\to \pi^+\pi^-J/\psi$ width. Many models for their composition have been…