This review briefly outlines recent experimental results from the charmonium system. These include new measurements of the M1 radiative transition rates $B(ψ(1S,2S)\toγη_c(1S))$; new insights into the mass of the $η_c(1S)$; the observation of $J/ψ(1S)$ decays to three photons; new measurements of the two-photon widths of the $χ_{cJ}(1P)$; the observation of radiative decays of the $χ_{cj}(1P)$ to light quarks; a precise measurement of the $h_c(1P)$ mass; and an update on properties of the $η_c(2S)$. Each result adds piecemeal to our understanding of the strong force.
The CLEO-c Experiment has made several recent contributions to the study of charmonium decays. This review briefly outlines the CLEO-c analyses of charmonium that were completed or made public during 2010. Special attention is given to the discovery of the process e+e- to pi+pi-h_c at a center of mass energy of 4170 MeV.
During the last few years there has been a renaissance in charm and charmonium spectroscopy with higher precision measurements at the $ψ^{'}$ and $ψ(3770)$ coming from BESII and CLEOc and many new discoveries coming from B-factories. In this paper, I will review the status of $ψ(3770)$ and below.
We review recent charmonium and charmonium-like state from the BaBar B-factory. A particular focus is given to the observation of the decay $X(3872) \to J/ψω$ and to recent $η_{c}(1S)$ and $η_{c}(2S)$ results. The Observation of the $χ_{c2}(2P)$ state will be also discussed
Recent results from BES and CLEOc experiments on charmonium decays using J/psi, psi' and psi'' data samples collected in e+e- annihilation are reviewed, including the measurement of the relative phase between strong and electromagnetic decays of psi', the study of the ``rho pi puzzle'' in J/psi and psi' decays, and the search for the non-DDbar decays of psi''. The decays of chi_cJ produced in psi' radiative transition are also reviewed. These new results shed light on the understanding of QCD.
In this talk, I review the recent experimental developments on charmonium. These mainly include the precision measurements of spin-singlet states $\etac$, $\etac(2S)$, $h_c$, studies of the charmonium-like states X(3872) and the $Y$ states. Charmonium transitions and decays are also discussed.
The charmonium-like states, Y(4260), Y(4350), produced via initial state radiation, as well as the X(3872), and Y(3940), produced in B meson decays from the BABAR B-factory are reviewed. These mesons do not seem consistent with conventional charmonium models, and several alternate hypotheses have been proposed to explain these new discoveries.
A brief review of experimental results on charmonium and charmonium-like hadron spectroscopy at B-factories is presented. A special focus is put on recent results of eta_c and eta_c(2S) study, X(3872) radiative decays, omega J/psi final state study and search for charmonium production in radiative Upsilon decays.
Recent results on Charmonium decays are reviewed which includes two-, three- and four-body decays of $χ_{cJ}$ states, observations of Y(4260) through $ππJ/ψ$ transitions, precise measurements of $M(D^0)$, $M(η)$ as well as $\mathcal{B}(η\to X)$.
The review on experimental results on charmonium and charmonium-like spectroscopy from B-factories is presented. Main theoretical interpretations, such as conventional charmonium, molecular state, hybrids, tetraquarks and others are discussed.
We review recent charmonium and bottomonium spectroscopy results from the B-factories Belle and \babar. A particular focus is given to the new $η_{c}(1S)$ and $η_{c}(2S)$ measurement and to the radiative transitions from $Υ(2S)$ and $Υ(3S)$ with converted photons.
In 2009, the BESIII experiment has collected about 225M $\jpsi$ and 106M $\psip$ samples, both of which are the world largest on-peak charmonium production. Based on these dataset, BESIII has made great effort on the study of the charmonium decays, some important of which have been reviewed in this proceeding. In addition, a searching for new physics through the $CP/P$ violation process is reported.
Recently, LHCb experiment announced a 3.5$σ$ evidence for direct CP violation in $D^0$ decay by looking at the difference between $A_{CP}(D^0\rightarrow K^+K^-)$ and $A_{CP}(D^0\rightarrow π^+π^-)$. This is the first evidence of CP violation in charm system, which may indicate new physics beyond the Standard Model. Motivated by this measurement, we review rare processes in charmonium decay, especially, the weak decay, $C$ or $P$ violated decay and lepton flavor violated decays. In case the new physics appears in charm sector, these rare decays of charmonium states will provide opportunity to s…
I review the recent $B$-factory measurements of new states which, in some cases, exhibit Charmonium-like properties, and in other cases suggest the existence of a new spectroscopy. Several theoretical interpretations of the new states have come to the fore although, at time of writing, we are no closer to untangling the nature of most of the particles making up the observed new zoo of states.
Recent results in studies of bottomonium especially relevant to charmonium are reviewed. This report covers dipion transition matrix elements, $η$ production in $Υ$ transitions, $Υ$ decays to invisible particles, a search for a non-standard-model pseudoscalar Higgs in $Υ$ radiative decays, and $Υ$ radiative decays to $\rm{f_2(1270)}$, $η$, and $η'$.
In this talk, we review the recent experimental developments on charmonium and charm spectroscopy base on the data samples taken by the BESIII, Belle, LHCb and CMS experiments. We concentrate on the resonant parameter measurement of $χ_{cJ}$, $η_{c}$, $η_{c}(2S)$, observation of $ψ(1^{3}D_{3})$ candidate and alternative $χ_{c0}(2P)$ candidate, observation of excited $B_{c}$ states, $Ξ(2930)$ states, excited $Ω_{c}$ states and doubly charm baryon, and the study of $Λ_{c}^{*}$ states.
The recent results on charmonium and charmoniumlike states from Belle experiment are reviewed. We summarise searches in $B$ decays for possible $X$-like states in final states containing $η_c$. The new measurement of $e^+e^-\toπ^+π^-ψ(2S)$ improves the determination of the properties of $Y(4360)$ and $Y(4660)$. The fits including $Y(4260)$ are performed. Evidence for a charged charmoniumlike structure at $4.05~{\rm GeV}/c^2$ is observed in the $π^{\pm}ψ(2S)$ intermediate state in the $Y(4360)$ decays. Belle also updates the measurement on $e^+e^-\to KKJ/ψ$ via initial state radiation using the…
In this talk, I review the recent experimental results on charmonium spectroscopy from BESIII, Belle, BaBar and CLEOc. Below the open-charm threshold, the masses and widths of spin-singlet states eta_c, eta_c(2S), h_c are measured with high precision. Above the threshold, chi_{c2}(2P) is identified in the process gamma gamma -> chi_{c2}(2P) -> gamma D bar{D}; Evidence of X(3823) is found in the M(chi_{c1} gamma) invariant-mass distribution for B -> gamma chi_{c1} K decays, the measured properties are consistent with the missing psi_2(1^{2}D_2) state.
In this report I review some results on the charmonium and light hadron spectroscopy mainly from BESIII and Belle experiments. For the charmonium, the contents include the observation of $ψ(4040)/ψ(4160) \to η\jpsi$, the measurements of the $η_c/η_c(2S)$ resonance parameters and their decays, the evidence of the $ψ_2(1^3D_2)$ state in the $χ_{c1}γ$ mass spectrum. For the light hadron spectroscopy, the contents include the $X(1835)$ research in $e^+e^- \to \jpsi + X(1835)$ and $γγ\to η' π^+ π^-$ processes, and the analysis of the $ηη$, $ωϕ$, $ϕϕ$ and $ωω$ mass spectra in low mass region.
We review some recent progress in understanding various exclusive double charmonium production processes at $B$ factories, within the nonrelativistic QCD factorization framework. First we investigate the impact of the joint perturbative and relativistic correction on the process that has attracted a great amount of attention in the past decade, $e^+e^-\to J/ψ+η_c$. We then briefly discuss the phenomenological implication of the next-to-leading order perturbative correction to the processes $e^+e^-\to J/ψ+χ_{c0,1,2} (η_{c2})$. We further emphasize a novel theoretical challenge, which is recentl…
Recent experimental results on charmonium $h_c(^1P_1)$, $η_c(1S)$ and $η_c(2S)$ from Belle, BaBar, CLEO and BESIII are reviewed. $h_c$ production and properties, the $η_c(1S)$ lineshape and the observation of $η_c(2S)$ in $ψ'$ decays are discussed.
The recent results on Charmonium and Charmonium-like states at BESIII are reviewed, including the observation of $\rm Z_{cs}(3985)$ state, the study of the new decay modes of $ψ_2(3823)$ state, observation of resonance structure in $\rm e^+e^- \to π^+π^-ψ_2(3823)$ process, the study of the $\rm e^+e^- \to K^+K^-J/ψ$ process, cross section measurement of $\rm e^+e^- \to ωπ^0$ and $ωη$ process, branching fraction measurement of $ψ(3686)\to\barΣ^0Λ+ c.c.$ process. Decay channels for $χ_{cJ} \to Λ\barΛ$, $χ_{cJ} \to Λ\barΛη$, $ψ(3686) \to Λ\barΛω$ and $η_c(2S)\to3(π^+π^-)$ are also discussed. The …
We review selected lattice results on the charmonium spectrum and first attempts to search for the existence of exotic states. The hadro-quarkonium model was proposed to interpret some of the exotic states as a quarkonium core inside a hadron. We present a lattice study of the hadro-quarkonium model in the limit of static quarks. The charm quark decouples in low energy observables and binding energies of charmonium. In a model calculation we are able to evaluate the corrections to decoupling of the charm quark in the continuum.
e+e- Experiments producing charmonium are reviewed. It is found that the contribution of the continuum amplitude via virtual photon was neglected in almost all the experiments and the channels analyzed. It is shown that the contribution of the continuum part may affect the final results significantly in psi(2S) and psi(3770) decays, while the interference between continuum and resonance amplitudes may even affect the J/psi decays as well as the psi(2S) and psi(3770). This should be considered in analyzing the "rho-pi puzzle" between J/psi and psi(2s) decays, and the difference between inclusiv…
The BESIII experiment at BEPCII at IHEP in Beijing/China has collected the world largest data sets in the $τ$-charm region and it is well suited to cover a rich hadron physics programme, including charmonium and open-charm spectroscopy, $R$-scan or electromagnetic form factor measurements, and many more. In particular, the unique data sets between 3.8 and 4.6\,GeV allow for discoveries and precision measurements of the interesting charmonium-like (exotic) `XYZ' states. The recently published precision cross-section measurement for $Y$ states is discussed as well as the first observation of the…
We review recent measurements of pure neutral final state production, gamma gamma to pi0 pi0 and eta pi0, and observations of new charmoniumlike resonances, X(3915) and X(4350), in the two-photon processes at the Belle experiment.
We review the most recent experimental progress in the hadron spectroscopy, up to bottomonium mass. This covers the search for the J^PC=1^-+ exotic state, the states in J/psi decays, the spin-singlets of heavy quarkonium, and the charmoniumlike XYZ states.
New results on properties and decays of open charm and charmonium states are reviewed. The emphasis is on examples that illustrate the various aspects through which studies of charm physics impact the field.
The discovery of numerous new charmonium-like structures since 2003 have revitalized interest in exotic meson spectroscopy. These structures do not fit easily into the conventional charmonium model, and proposals like four-quark states, hybrids, and re-scattering effects have been suggested as explanations. Since 2009, several new structures were reported in the $J/ψϕ$ mass spectrum with the following characteristics: they are the first ones reported decaying into two heavy mesons which contain both a $c\bar{c}$ pair and a $s\bar{s}$ pair; and their masses are well beyond the open charm pair t…
A selection of results from electron-positron collisions at BESIII are reviewed. The results presented here illustrate the wide range of physics topics that can be studied using the Beijing Electron Positron Collider~(BEPC). At low collision energies, the cross section for $e^+e^-\to π^+π^-$ provides much-needed input into theoretical calculations of the anomalous magnetic moment of the muon, and the reaction $e^+e^-\to p\bar{p}$ provides access to the electromagnetic form factors of the proton. In the charmonium region, a large sample of $ψ^\prime$ decays can be used to measure new decay mode…
Recent results on the search for pentaquarks and on charmonium spectroscopy at BaBar are reviewed. The latter includes the observation of the puzzling new state X(3872) -> J/psi pi+ pi- in B decays, and the searches for X(3872) in two-body B decays and initial state radiation events.
This talk reviews an unrepresentative selection of Belle's open-charm and charmonium analyses, focussing on new developments and topics of interest to the DIS community. Highlights include an X(3872) analysis favoring J^PC = 1++, and the D0-D*0bar bound-state interpretation.
We review the most recent results from experiments studying systems containing charmed quarks. The selection reflects the presenter's bias, and there is an emphasis on decays of open charm. We discuss precision measurements of various sorts, various new states in the charmonium system, measurements aimed at testing Lattice QCD, and the latest searches for charm mixing. We conclude with a discussion of upcoming experiments at existing and future facilities.
We present the most recent results from the BESIII experiment. This review covers the studies of charmonium decays, light hadron spectroscopy and charm physics. Especially, the prospects for weak decays of charm mesons are addressed at the BESIII.
With the help of the largest data samples of $J/ψ$ and $ψ(2S)$ events ever produced in $e^+e^-$ annihilations, the three singlet charmonium states, $η_c(1S)$, $η_c(2S)$ and $h_c(1P)$, have been extensively studied at the BESIII experiment. In this review, a survey on the most recent results, including a series of precision measurements and observations of their new decay modes, is presented, which indicates the further investigations on their decays are needed to understand their decay mechanisms and have precision tests of the theoretical models. At present, about eight times larger data samp…
This paper briefly reviews the striking experimental observation of a ridge-like dihadron correlation structure in high multiplicity proton-proton collisions at the Large Hadron Collider (LHC). Recent progress of both experimental and theoretical efforts on understanding the physical origin of the novel effect is reviewed. Outlook on future direction of possible new studies is discussed.
