Related papers: Heavy quarkonia: the beauty and the beasts
We give a pedagogical introduction to heavy quarkonia -- bound states of a heavy quark and its antiquark (e.g., charmonium $c\bar{c}$, bottomonium $b\bar{b}$) -- as well as to the exotic hadrons containing two heavy quarks that have been…
Recent experimental results on heavy quarkonia spectroscopy and decays are reviewed. In particular, new results are discussed on charmonium spin singlet states, bottomonium D-states, photon and hadronic transitions from heavy quarkonium…
The bottomonium spectrum is the perfect testing ground for the confining potential and unitarisation effects. The bottom quark is about three times heavier than the charm quark, so that $b\bar{b}$ systems probe primarily the short-range…
Motivated by recent experimental observations of charmonium(-like) states, we investigate their interpretation as conventional charmonium states within the framework of relativized quark potential model. We find a consistent description of…
Charmonium spectroscopy gained renewed interest after the discovery in 2003 of the unpredicted X(3872) charmonium-like state, above the $D\overline{D}$ threshold. To date many charmonium-like states above the $D\overline{D}$ threshold have…
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…
We calculate the masses and leptonic decay widths of the bottomonium $b\bar b$ and charmonium $c\bar c$ states in a constituent quark model where the Cornell-like potential and spin-dependent interaction are employed, with all model…
In the last years, the CLEO III experiment has recorded a large collection of data sets at the Y(1S), Y(2S), Y(3S) and psi(2S) resonances. Preliminary results of studies of these data sets are shown here, which include the observation of a…
To illustrate the campaign to understand heavy quarkonium systems, I focus on a puzzling new state, $X(3872) \to \pi^+\pi^- J/\psi$. Studying the influence of open-charm channels on charmonium properties leads us to propose a new charmonium…
We discuss a general theoretical framework for the study of bound states made of two heavy quarks. For states below threshold, the framework has been developed to the level of providing precision studies for several charmonium and…
Using proton-proton collision data, corresponding to an integrated luminosity of 9$fb^{-1}$, collected with the~LHCb detector between 2011 and 2018, a new narrow charmonium state, the $X(3842)$ resonance, is observed in the decay modes…
Starting from a molecular picture for the X(3872) resonance, this state and its J^{PC}=2++ HQSS partner [X2(4012)] are analyzed within a model which incorporates possible mixings with 2P charmonium states. Since it is reasonable to expect…
The X(3872) is studied as an axial-vector charmonium state in the multichannel framework of the Resonance-Spectrum-Expansion quark-meson model, previously applied to a variety of other puzzling mesonic resonances. Included are the…
We study the spectral function of the axial-vector charmonium state $\chi_{c1}(2P)$ coupled to $DD^{\ast}$ mesons, by employing a quantum field theoretical approach: a pronounced enhancement close to the $D^{0}% D^{\ast0}$ threshold, to be…
We estimate the binding energies of charmonium ($J/\psi$, $\psi(2S)$, $\psi(1D)$, $\chi_{c0}$, $\chi_{c1}$, $\chi_{c2}$) and bottomonium ($\Upsilon(1S)$, $\Upsilon(2S)$, $\Upsilon_2(1D)$, $\chi_{b0}$, $\chi_{b1}$, $\chi_{b2}$) states bound…
Charmonium(-like) or bottomonium(-like) states, which are incompatible with predictions from a static quark anti-quark potential model, are often refered to as XYZ states. In this lecture, some peculiar properties of states such as the…
We calculate the masses of $\chi_{\rm c}(2P)$ and $\chi_{\rm b}(3P)$ states with threshold corrections in a coupled-channel model. Here, the meson quarkonium core is augmented by higher Fock components due to pair-creation effects.…
Focusing on recent measurement of $B^+ \to D_s^+D_s^-K^+$ process given by the LHCb Collaboration, we propose that this newly observed near the $D_s^+D_s^-$ threshold enhancement can be due to the contribution of the $\chi_{c0}(2P)$, which…
We construct spectra of decays of the resonance X(3872) with good analytical and unitary properties which allows to define the branching ratio of the X(3872) \to D^{*0}\bar D^0 + c.c. decay studying only one more decay, for example, the…
The nature of the X(3872) enhancement is analysed in the framework of the Resonance-Spectrum Expansion, by studying it as a regular $J^{PC}=1^{++}$ charmonium state, though strongly influenced and shifted by open-charm decay channels. The…