Related papers: Hadronic resonances enhanced by thresholds
The interaction of the charmed baryon and the anticharmed meson is assumed to be realized by exchanging a scalar meson of $f_0(500)$, and then these systems are studied by solving the Schrodinger equation, respectively. When the pentaquarks…
We have studied the meson-baryon $S-$wave interaction, using coupled channels, in the isoscalar hidden-charm strange sector and $J^P = 1/2^-,3/2^-$ and $5/2^-$. We impose constraints of heavy quark spin symmetry in the interaction and…
The proper description of hadronic decays of baryon resonances has been a long standing problem in soliton models for baryons. In this talk I present a solution to this problem in the three flavor Skyrme model that is consistent with…
Relativistic light-front bound-state equations for double-heavy mesons, baryons and tetraquarks are constructed in the framework of supersymmetric light front holographic QCD. Although heavy quark masses strongly break conformal symmetry,…
We study N and $\Delta$ hidden-charm baryon resonances that are generated dynamically from the s-wave interaction of pseudoscalar and vector mesons with $1/2^+$ and $3/2^+$ baryons. We use a unitary coupled-channels model that fulfills…
Many charmonium-like and bottomonium-like $XYZ$ resonances have been observed by the Belle, Babar, CLEO and BESIII collaborations in the past decade. They are difficult to fit in the conventional quark model and thus are considered as…
In the heavy-quark limit, the two heavy quarks in a doubly heavy baryon or a doubly heavy tetraquark are bound by their color-Coulomb potential into a compact diquark. The doubly heavy hadrons are related by the approximate…
We consider the interplay of a quark state and a hadronic threshold in the framework of the P-matrix formalism, which is reviewed and extended for use together with conventional methods of computing quark-gluon dynamics. We provide 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…
At the chiral restoration/deconfinement transition, most hadrons undergo a Mott transition from being bound states in the confined phase to resonances in the deconfined phase. We investigate the consequences of this qualitative change in…
It is argued that the observed enhancement of the hadronic transition Upsilon(4S) -> Upsilon(1S) eta relative to Upsilon(4S) -> Upsilon(1S) pi pi can be explained if the resonance Upsilon(4S) contains an admixture of a four-quark component,…
We review the chromoelectric and chromomagnetic mechanisms that tentatively lead to stable or metastable multiquark configurations. An alternative interpretation of the dynamics is the quark interchange between hadrons, as illustrated in…
Full or empty narrow bands near the Fermi level are known to enhance superconductivity by promoting scattering processes and spin fluctuations. Here, we demonstrate that doublon-holon fluctuations in systems with half-filled narrow bands…
In the framework of the quark delocalization color screening model (QDCSM), we systematically investigate the double-charm and double-strange tetraquark systems $cc\bar{s}\bar{s}$ with two structures: meson-meson and diquark-antidiquark.…
The effects of charmed meson loops on the spectrum of charmonium are considered, with special attention paid to the levels above open-charm threshold. It is found that the coupling to charmed mesons generates a structure at the D \bar{D}*…
There are theoretical and phenomenological motivations that there may exist additional heavy Z' bosons with family non-universal couplings. Flavor mixing in the quark and lepton sectors will then lead to flavor changing couplings of the…
The regularities in the spectrum of the light baryon resonances are reviewed and compared with those of the light mesons. We discuss the occurrence of parity doublets and clusters, and note the trends in the values of the masses, widths,…
Many new results on hadron spectra have been appearing in the past few years thanks to improved experimental techniques and searches in new channels. New theoretical techniques including refined methods of lattice QCD have kept pace with…
The diabatic framework generalizes the adiabatic approximation built into the Born-Oppenheimer (BO) formalism, and is devised to rigorously incorporate the mixing of BO-approximation eigenstates with two-particle thresholds. We recently…
In this work we discuss the practical and conceptual issues related to quark-hadron-duality in heavy-heavy systems. Recent measurements in the charmonium region allow a direct test of quark-hadron-duality. We present a formula for…