We report on the observation of the charm mesons D^\ast \pm, D^\pm and D_s ^\pm with 1.4 nb^-1 of data, and of the J/psi-->mu+mu- resonance with 78 nb-1 of data from the ATLAS detector in 7 TeV proton-proton collisions at the LHC. The resultant signals support the high performance of the ATLAS detector as predicted from simulation and prospects for future measurements in the charm and charmonium sector.
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
New results of the Belle experiment at the KEKB asymmetric e^+e^- collider are presented, in particular (a) measurement of the mass and width of the $η_c$ and $η_c'$ in B meson decays, (b) measurement of the mass, width and quantum numbers of the X(3872) and (c) observation of the $χ_{c2}$ in $B$ meson decays.
We report on measurements of time-dependent CP-violation asymmetries in neutral B meson decays to charmonium and charm final states. The results are obtained from a data sample of 467+/-5 million Y(4S)->BBbar decays collected with the BaBar detector at the PEP-II B factory.
Some recent results from the Fermilab fixed-target experiment E789 on production of charm, charmonium, and beauty are summarized and compared to model predictions. The data indicate that heavy-quark and quarkonium production are not yet entirely understood. The largest discrepancy concerns the rate of $ψ^\prime$ production, which is a factor $\approx$25 above expectations.
We report measurements of charmonium resonances (J/Psi, Psi(2S),Chi_c1) using about 25 fb^-1 of data collected by the BABAR detector around the Upsilon(4S) resonance. We present measurements of inclusive charmonium production of charmonium in B decays and from the continuum, as well as exclusive branching ratios of B mesons into charmonium final states. We present also a measurement of the B0 -> K*0 gamma branching ratio and a search for the decay B0 -> gamma gamma.
We present recent results on charmonium and charmonium-like states from the BaBar B-factory located at the PEP-II asymmetric-energy $e^{+}e^{-}$ collider at the SLAC National Accelerator Laboratory.
We present measurements of charmonium and bottomonium production using a data sample collected by CDF during the 1992-93 p-pbar collider run at the Fermilab Tevatron.
Over the past few years, there has been a lot of progress in the areas of charm and charmonium spectroscopy, in large part due to the very large data samples being accumulated at the e+e- B-Factories. In this presentation I will focus on results in three areas: the X/Y/Z charmonium-candidate states, the D_sJ charmed-strange mesons, and newly-discovered charmed baryons. Note the absence of a section on pentaquarks: all B-Factory searches for pentaquarks, charmed or otherwise, have not yielded any observation of such states.
An overview is given of the results on charmonium production obtained by the ATLAS collaboration at the LHC. Recent preliminary measurements covering prompt and non-prompt production of $J/ψ$ and $ψ(2S)$ states in the range of high transverse momenta from 60 to 360~GeV are highlighted.
The asymmetric B-factories have provided valuable information on CP violation so far. In particular, one of the angles of the Unitarity Triangle, phi1(=beta), has been measured by several approaches. Since FPCP2004, some measurements have been updated and improved. In this letter, the latest status of phi1 measurements, performed at BaBar and Belle experiments usgin B -> charm/charmonium decays, are reported.
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 search for centrally produced charmonium states has been presented. There is no significant evidence for any charmonium production. An upper limit of 2 nb is found for the cross section of chic production using the decay chic(1P)-> J/psi gamma.
We report the first observation of a new charmonium state at a mass of $(3.943 \pm 0.006 \pm 0.006) {GeV}/c^2$. This state, called X(3940), is observed in the process $e^+ e^- \to J/ψX(3940)$ in the spectrum of masses recoiling against a reconstructed $J/ψ$. We also observe the decay of the X(3940) into $D^* \bar{D}$ and measure the intrinsic width of this state to be less than $52 MeV/c^2$ at the 90% C.L. These results are obtained from a $350 fb^{-1}$ data sample collected with the Belle detector near the $Υ(4S)$ resonance, at the KEKB asymmetric energy $e^+ e^-$ collider.
We see copious production of charmed hadrons in the early LHCb data. The status and plans for charm production studies at LHCb are discussed, and preliminary signals are shown.
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.
We report the latest outcomes for the Charmonium system investigation on 226x10^6 J/Psi and 106x10^6 Psi' events collected with the BESIII detector at the BEPCII e+e- collider.
Fermilab experiment E835 has done an extensive set of studies on charmonium triplet P states. The most precise measurements on mass and total width come indeed from charmonium spectroscopy by direct formation of $c\bar{c}$ states in $\bar{p}p$ annihilations. Results on both partial widths and higher multipoles radiative transitions $χ_{cJ} \to J/ψγ\to γe^+ e^-$ are given, together with the $γγ$ widths of $χ_{c0}$ and $χ_{c2}$. For the first time in hadronic charmonium production, hadronic annihilation channels ($π^0 π^0$ and $ηη$) have been clearly identified at the $χ_{c0}$ resonance.
We report recent results on the properties of the X(3872) produced via the B-->KX(3872) decay process in the Belle detector. We compare these properties with expectations for possible charmonium-state assignments.
In this talk, we will present the results on the charmonium spin singlet states below the open charm threshold, including h_c, η_c, and η_c(2S). The masses, widthes, and production rates of these states will be reported. The results are based on a data sample of 106 million ψ' events collected with the BESIII experiments at the BEPCII collider.
Using a sample of >10^5 J/psi to mu+mu- decays, Fermilab experiment 789 has studied production of J/psi and psi-prime in 800-GeV proton-nucleon collisions. Differential cross sections and nuclear dependences have been measured for charmonium as well as for charm and beauty production. While charm and beauty production are consistent with perturbative QCD calculations, charmonium cross sections exceed the predictions of the color-singlet model by large factors, suggesting that additional mechanisms (such as color-octet production) may play important roles. Nuclear dependences of production cros…
We present the study of CP violation in charm and charmonium decays, using a data sample corresponding to 657 \times 10^6 BBbar events collected with the Belle detector at the Υ(4S) resonance at the KEKB asymmetric-energy e^+e^- collider. We report measurements of the polarization fraction and time-dependent CP-violation parameters of the decay B^0\to D^{*+}D^{*-} and of the branching fraction and charge asymmetry in the decay of the Cabibbo- and color-suppressed process B^{\pm} \to ψ(2S) π^{\pm}.
We present recent results from charmonium and open charm production at the LHCb experiment at CERN, Geneva. We concentrate on studies for the measurement of the cross section pp ->JPsi+X in its decay channel with two muons, showing the agreement of the simulation with the data in few key distributions. We also show the reconstructed modes of D0->K-pi+, D0 K-pi+pi0, LambdaC+ -> p K-pi+ and D+ ->Ks0 pi+ and their prospects.
We report on exclusive decays of B mesons into final states containing charmonium using data collected with the BABAR detector at the PEP-II storage rings. The charmonium states considered here are J/psi, psi(2S), and chi_C1. Branching fractions for several exclusive final states, a measurement of the decay amplitudes for the B0 --> J/psi K* decay, and measurements of the B0 and B+ masses are presented. All of the results we present here are preliminary.
We report BELLE measurements of the exclusive cross sections for the processes e+e-->DD*, e+e-->DD, e+e-->DDpi, the first observation of psi(4415)-> DD*2(2460)bar decay and new state, Y(4660), using ISR. In addition, another cluster of events at around 4.05GeV/c2 is reported.
While the charmonium model has been effective in describing ccbar bound mesons, there have been many recently discovered charmonium-like states it cannot accommodate. Here I provide a review of recent results from the B-factories including the X(3872), three new particles in the mass range near 3.93 GeV, and four new resonances in initial state radiation (ISR) decays.
We propose to investigate various charmonium states using their common decay channel to p pbar at LHC. Having the branching ratios for charmonium decaying into the p pbar final state measured or calculated, we propose to measure the charmonium production rate for both hadroproduction including soft-diffraction and inclusive production from b-hadron decays. We discuss the theoretical impacts in QCD of measuring different charmonium production rates and also the experimental prospects at LHCb, in particular, those for yet unmeasured eta_c and h_c.
I give an overview of the current status of the theory of charmonium production in hard-scattering processes and summarize the present state of comparisons between theory and experiment.
In this paper we confront both the hadronic molecule and the hadro-charmonium interpretations of the $\y$ with the experimental data currently available. We conclude that the data support the $\y$ being dominantly a $D_1\bar D+c.c.$ hadronic molecule while they challenge the hadro-charmonium interpretation. However, additional data is necessary to allow for stronger conclusions.
Recent data on charmonium production in B-meson decays suggest that charmonium hybrid mesons with mass ~4 GeV may be produced in B-decay via c\bar{c} colour octet operators. Some of these states are likely to be narrow with clean signatures to J/ψpi^+ pi^- final states. Experimental signatures and search strategies for existing B-factories are described.
The open-charm strong decays of higher charmonium states up to the mass of the $6P$ multiplet are systematically studied in the $^3P_0$ model. The wave functions of the initial charmonium states are calculated in the linear potential (LP) and screened potential (SP) quark model. The decay widths for most of the well-established charmonium states above the open-charm thresholds can be reasonably described. By comparing our quark model calculations with the experimental observations we also discuss the nature of some of the newly observed charmonium-like states. It is found that (i) the $ψ(4415)…
The Fermilab SeaQuest experiment has measured dimuon events from the interactions of 120GeV proton beam on liquid hydrogen and deuterium targets with dimuon mass between 2 and 9GeV. These dimuon events contain both the Drell-Yan process and the charmonium ($J/ψ$ and $ψ^\prime$) production. Unlike the Drell-Yan process which probes the antiquark distributions in the nucleons, the charmonium production is sensitive to both quark and gluon distributions. SeaQuest has extracted the $σ^{pd}/2σ^{pp}$ ratio as well as the differential cross sections for charmonium production in the kinematic region o…
Studies of charmonium properties and production mechanism started with the discovery of $J/ψ$ meson. Since more than 40 years the charmonium production mechanism is still not entirely understood. Following the era of investigations at $e^+e^-$ machines, nowadays, charmonium states are copiously produced at hadron colliders, that allows systematic studies of their resonance parameters, production observables and decays. Despite large production rates, many charmonium states are barely studied due to the complications of their reconstruction against a large background level. The LHCb experiment …
This article presents recent results of the Z boson production in the proton-lead collisions and the charmonium production in the ultra-peripheral lead-lead collisions at the LHC collected during 2013 to 2018 by the LHCb detector. The potential heavy ion programs in these topics are also discussed.
Based on the updated data of charmoniumlike state $Y(4220)$ reported in the hidden-charm %and open-charm channels of the $e^+e^-$ annihilation, we propose a $4S$-$3D$ mixing scheme to categorize $Y(4220)$ into the $J/ψ$ family. We find that the present experimental data can support this charmonium assignment to $Y(4220)$. Thus, $Y(4220)$ plays a role of a scaling point in constructing higher charmonia above 4 GeV. To further test this scenario, we provide more abundant information on the decay properties of $Y(4220)$, and predict its charmonium partner $ψ(4380)$, whose evidence is found by ana…
This report discusses some recent investigations of the heavy hadron spectra using lattice QCD. The first half addresses multiple precision determinations of the masses of charm (and bottom) baryons. Recent lattice results in the tetraquark and the dibaryon sectors are also presented. The second half focuses on new exploratory studies of the excited charmonium spectra in the vector and scalar channels. Along the way, lattice results are compared with the experimental results, wherever they are available.
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.
We propose the initial single chiral particle emission mechanism, with which the hidden-charm di-kaon decays of higher charmonia and charmonium-like states are studied. Calculating the distributions of differential decay width, we obtain the line shape of the $J/ψK^+$ invariant mass spectrum of $ψ_i\to J/ψK^+K^-$, where $ψ_i=ψ(4415), Y(4660)$, and $ψ(4790)$. Our numerical results show that there exist enhancement structures with both hidden-charm and open-strange decays, which are near the $D\bar{D}_s^*/D^*\bar{D}_s$ and $D^*\bar{D}_s^*/\bar{D}^*{D}_s^*$ thresholds. These charged charmonium-li…
The effects of intermediate charmed mesons on charmonium transitions with the emission of one pion or eta are studied systematically. Based on a non-relativistic effective field theory we show that charmed meson loops are enhanced compared to the corresponding tree-level contributions for transitions between two S-wave charmonia as well as for transitions between two P-wave charmonia. On the contrary, for the transitions between one S-wave and one P-wave charmonium state, the loops need to be analyzed case by case and often appear to be suppressed. The relation to and possible implications for…
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 charmonia $ψ(4040)$, $ψ(4160)$, $ψ(4415)$ and charmonium-like state Y(4260). We suggest BESIII to search for these structures in the $J/ψπ^+$, $ψ(2S)π^+$ and $h_b(1P)π^+$ invariant mass spectra of the $ψ(4040)$ decays into $J/ψπ^+π^-$, $ψ(2S)π^+π^-$ and $h_b(1P)π^+π^-$. In addition, the experimental search for these structures in the $J/ψπ^+$, $ψ(2S)π^+$ and $h…
