Related papers: Aspects of Charmonium

We investigate $2P$-$1F$ mixing in charmonium, focusing on the close-in-mass $\chi_{c2}(2P)$ and $\chi_{c2}(1F)$ states. The conventional tensor force yields negligible mixing, motivating the inclusion of coupled-channel effects. Our…

Thirty years ago, the suppression of charmonium production in heavy-ion collisions was first proposed as an unambiguous signature for the formation of a Quark-Gluon Plasma. Since then, experiments at fixed-target accelerators (SPS) and…

We study relativistic charmonium on very fine quenched lattices (beta=6.4 and 6.6). We concentrate on the calculation of the hyperfine splitting between eta_c and J/psi, aiming for a controlled continuum extrapolation of this quantity.…

The extend to which geometrical effects contribute to the production and suppression of the $J/\psi$ and $q\bar{q}$ minijet pairs in general is investigated for high energy heavy ion collisions at SPS, RHIC and LHC energies. For the energy…

Many exotic charmonium resonances have been identified recently in experiment, however their nature and properties are mostly unknown. Algorithmic and theoretical progress in lattice calculations has enabled reliable numerical investigation…

This paper reports the first multi-channel joint analysis to identify the properties of the exotic charmonium-like state $T_{c\bar{c}}(4020)$ via the electron-positron annihilation process $e^{+}e^{-}\to\pi^{+}T_{c\bar{c}}(4020)^{-}+c.c$. A…

We compute the decay rates and $H$-energy distributions of $B$ mesons into the final state $H+X$, where $H$ can be any one of the $S$-wave or $P$-wave charmonia, at next-to-leading order in the strong coupling. We find that a significant…

Production of J/$\psi$ from nucleus-nucleus reactions depends sensitively on the dissociation cross section with light hadrons. Effective lagrangian methods are used to describe the hadronic degrees of freedom, including strangeness and…

It is shown that the study of the \omega-\rho interference pattern in the J/psi -> (rho+omega)eta -> pi+pi-eta decay provides evidence for the large (nearly 90 degrees) relative phase between the isovector one-photon and three-gluon decay…

We briefly review the theoretical and experimental results concerning decays of positronium. Possible solutions of the "orthopositronium lifetime puzzle" are discussed. Positronium annihilation into neutrinos is examined and disagreement is…

We present a systematic and selfconsistent analysis of four-quark charmonium states and applied it to study compact four-quark systems and meson-meson molecules. Our results are robust and should serve to clarify the situation of charmonium…

The first measurement of ${C\!P}$ asymmetries in the decay ${B_s^0\to J/\psi \overline{K}^{*}(892)^{0}}$ and an updated measurement of its branching fraction and polarisation fractions are presented. The results are obtained using data…

By extracting the transition amplitudes, we give the first lattice QCD prediction of the two-body decay partial widths of the $1^{-+}$ charmoniumlike hybrid $\eta_{c1}$. Given the calculated mass value $m_{\eta_{c1}}=4.329(36)$ GeV, the…

New enhancements in the charmonium and bottomonium spectra observed since 2003 are very briefly reviewed. Special attention is paid to $\chi_{c1}(3872)$ (formerly $X(3872)$) owing to its remarkable proximity to the $\bar{D}^{\star0}\!D^0$…

In this work, we predict two charged charmonium-like structures close to the $D^\ast\bar{D}$ and $D^\ast\bar{D}^\ast$ thresholds, where the Initial Single Pion Emission mechanism is introduced in the hidden-charm dipion decays of higher…

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…

An isospin analysis of $B\to \pi\pi$ decays yields $\sin 2\alpha$, where $\alpha$ is the usual CKM angle $\alpha\equiv {\rm arg} [-V_{td} V_{tb}^\ast/(V_{ud}V_{ub}^\ast)]$ without hadronic uncertainty if isospin is a perfect symmetry. Yet…

The observation of many unexpected states decaying into heavy quarkonia has challenged the usual Q-Qbar interpretation. We will discuss the nature of some of the charmonium-like resonances recently observed by BES III and LHCb, and their…

Recent results on charmonia decays at BES/BEPC are reported, including the observation of psi'-->K_S K_L, psi'--> Vector + Tensor for the measurement of the relative phase between the strong and electromagnetic decays of psi' and a test of…

In this talk a short overview of $\eta$ and $\eta'$ decays is given with an emphasis on what can be learned for the strong interaction from them. The talk consists of a short introduction to ChPT, a discussion of $\eta\to3\pi$ beyond $p^4$…