Puzzles in charm spectroscopy

We briefly analyze aspects of open and hidden charm resonances, discussing in particular the mesons $D_{sJ}(2860)$ and X(3872).Comment: 8 pages, 4 figures. Invited talk given at the YKIS Seminar on New Frontiers in QCD: Exotic Hadrons and Hadronic Matter, Kyoto, Japan, 20 Nov. - 8 Dec. 200

Quarkonium dissociation in a far-from-equilibrium holographic setup

The real-time dissociation of the heavy quarkonium in a strongly coupled boost-invariant non-Abelian plasma relaxing towards equilibrium is analyzed in a holographic framework. The effects driving the plasma out of equilibrium are described by boundary quenching, impulsive variations of the boundary metric. Quarkonium is represented by a classical string with endpoints kept close to the boundary. The evolution of the string profile is computed in the time-dependent geometry, and the dissociation time is evaluated for different configurations with respect to the direction of the plasma expansion. Dissociation occurs fastly for the quarkonium placed in the transverse plane.Comment: 14 pages, 8 figures. References added. Matches the published versio

Identifying DsJ(2700)D_{sJ}(2700) through its decay modes

We study how to assign the recently observed $D_{sJ}(2700)$ meson to an appropriate level of the $c \bar s$ spectrum by the analysis of its decay modes in final states comprising a light pseudoscalar meson. We use an effective lagrangian approach with heavy quark and chiral symmetries, obtaining that the measurement of the $D^* K$ decay width would allow to distinguish between two possible assignments.Comment: RevTex, 6 pages - references adde

New meson spectroscopy with open charm and beauty

All the available experimental information on open charm and beauty mesons is used to classify the observed states in heavy quark doublets. The masses of some of the still unobserved states are predicted, in particular in the beauty sector. Adopting an effective Lagrangian approach based on the heavy quark and chiral symmetry, individual decay rates and ratios of branching fractions are computed, with results useful to assign the quantum numbers to recently observed charmed states which still need to be properly classified. Implications and predictions for the corresponding beauty mesons are provided. The experimental results are already copious, and are expected to grow up thanks to the experiments at the LHC and to the future high-luminosity flavour and $p-\bar p$ facilities.Comment: RevTex, 15 pages, 1 figure. Corrected Equations (8) and (9

X(3872)→DDˉγX(3872) \to D \bar D \gamma decays and the structure of X(3872)

It has been suggested that the radiative $X \to D \bar D \gamma$ decay modes are useful to shed light on the structure of the meson X(3872), since the ratio $R={\Gamma(X \to D^+ D^- \gamma) \over \Gamma(X \to D^0 \bar D^0 \gamma)}$ is expected to be small ($R \ll 1$) if $X$ is a molecular $D^{*0} \bar D^0$ state. We compute $R$ in a $\bar c c$ $J^{PC}=1^{++}$ description of $X$ finding that it is tiny in a wide range of hadronic parameters governing the decay. A discrimination between the molecular and $\bar c c$ description can be obtained through the analysis of the photon spectrum.Comment: LaTex, 12 pages, 5 figures, version accepted for publication in PL