Related papers: The 2^-+ assignment for the X(3872)

In 2021, the Belle collaboration reported the first observation of a new structure in the $\psi(2S) \gamma$ final state produced in the two-photon fusion process. In the hadronic molecule picture, this new structure can be associated with…

The ATLAS collaboration has reported excesses in searches for resonant diboson production decaying into hadronic final states. This deviation from the Standard Model prediction may be a signature of an extra bosonic particle having a mass…

An interesting controversy has emerged challenging the widely accepted nature of the $X(3915)$ and the $X(3930)$ resonances, which had initially been assigned to the $\chi_{c0}(2P)$ and $\chi_{c2}(2P)$ $c\bar c$ states, respectively. To…

A study of the two body decays $B^\pm\rightarrow X_{c\bar c}K^\pm$, where X$_{c\bar c}$ refers to one charmonium state, is reported by BaBar collaboration using a data sample of 424 fb$^{-1}$. The absolute determination of branching…

We study the mass splittings of $Q_1q_2\bar{Q}_3\bar{q}_4$ ($Q=c,b$, $q=u,d,s$) tetraquark states with chromomagnetic interactions between their quark components. Assuming that $X(4140)$ is the lowest $J^{PC}=1^{++}$ $cs\bar{c}\bar{s}$…

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…

Spectroscopy results for Belle and BaBar are reported. A particular focus is put on new results of the X(3872) state with its radiative decays to $J$/$\psi$$\gamma$ and $\psi'$$\gamma$, its decay into $J$/$\psi$3$\pi$ and the search for…

We show that the literature on pion exchange between charm and bottom mesons is inconsistent. We derive the formalism explicitly, expose differences between papers in the literature and clarify the implications. We show that the X(3872) can…

The ratio of branching fractions Br(X(3872) --> gamma J/psi)/ Br(X(3872) --> pi^+ pi^- J/psi) is studied by assuming that the X(3872) --> pi^+ pi^- J/psi decay proceeds through the rho^0 meson pole which is caused by the omega-rho^0 mixing.…

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 $c\bar c$ radial excitation or a D-wave state. It can't be a…

We discuss the likely tetraquark interpretation of the X(1576) K+ K- isovector resonance recently reported by BES with J^{PC}=1^{--}. We point out that if this interpretation as a four-quark state is correct, the (s u sbar dbar) tetraquark…

Data on B+ --> J/psi phi K+ and the Y(4140) enhancement recently reported by the CDF collaboration [arxiv:0903.2229] are analysed. The threshold behaviour, as well as traces of the X(4260) enhancement, the known c-cbar resonances psi(2D),…

We review hadron spectroscopy at BABAR with emphasis on recent results from the studies of the X(3872) state, inclusive charmonia on recoil, double charmonium production, and the broad structure observed at around 4.26 GeV/c^2. These…

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 $D \bar D^*$…

Assuming X(3872) is a $qc \bar q \bar c$ tetraquark and using its mass as input, we perform a schematic study of the masses of possible heavy tetraquarks using the color-magnetic interaction with the flavor symmetry breaking corrections.

The X(3872) with quantum numbers J(PC) = 1(++) is considered as a composite state containing both molecular hadronic and a c bar(c) component. Based on this structure assumption we first constrain model parameters in order to reproduce the…

The discovery of the $X(3872)$ meant the revival of the heavy meson spectroscopy beyond naive $q\bar q$ structures. Once that the $SU(3)$ scheme, which was very useful in the dawn of the quark models, does not work for these states, one has…

X (3872) because of its mass that is just below D^0 D-^0* threshold and its quantum number j^pc=1^++ can be considered as a weakly bound molecule. It can be regarded as a non-relativistic system depicting universality and compositeness.…

In this letter, we propose interpolating currents for the X(3872) resonance, and show that, in the Heavy Quark limit of QCD, the X(3872) state should have degenerate partners, independent of its internal structure. Magnitudes of possible…

Many new states in the charmonium and bottomonium mass region were recently discovered by the BaBar, Belle and CDF Collaborations. We use the QCD Sum Rule approach to study the possible structure of some of these states. In particular we…