International Journal of Modern Physics: Conference Series

I briefly review Non-Relativistic QCD and related effective theories, and discuss applications to heavy quarkonium decay, and production in electron-positron colliders.

I review the NRQCD factorization approach for quarkonium production and compare its predictions with measurements in hadron-hadron and ep collisions.

Intensive study of double charmonium production at B-factories has led to the considerable theoretical progress in understanding of charmonia production. In addition, double charmonium production process has served to search for new states.

We analyze the spectrum of charmonium above the threshold for the production of D mesons. Several recent intriguing experimental data have reopen the interest on charmonium spectroscopy and they deserve an special attention. We focus our study on the X(3872) and the possible existence of charged states contributing to the spectrum of charmonium

A Large Ion Collider Experiment (ALICE) is one of the four large experiments at the Large Hadron Collider (LHC), and the one dedicated to ultra relativistic heavy ion collisions, aiming at investigating the properties of the high-density state of QCD matter produced in such events. ALICE started to collect data in proton-proton collisions at the LHC at CERN in November 2009 (with a centre of mass energy ). Since March 2010 data are being recorded at an energy of while from November 7 to December 6 LHC provided Pb-Pb collisions at an energy of per nucleon-nucleon pair.

In Pb-Pb collisions heavy quarks are regarded as sensitive probes of the interaction dynamics between the parton and medium produced in the collisions, and the energies available at LHC will allow to study the production of heavy flavours with high statistics. Proton-proton data will be used to measure the heavy flavours production cross section to compare with perturbative QCD calculations in an unexplored energy domain and they will provide the reference for the study of Pb-Pb collisions. After a description of the ALICE experiment focused on its heavy flavour related performance, the status of the first analysis on charm production, measured by reconstructing the decays of D⁰, D⁺, D*⁺, and D_s into hadronic and semi-leptonic channels will be presented. An outlook of the same measurements for the upcoming Pb-Pb run will also be discussed.

I give a short review of the current status of lattice QCD calculations of the spectrum of charmonium.

Many new states in the charmonium mass region were recently discovered by the BaBar, Belle and CDF Collaborations. We use the QCD Sum Rule approach to study the possible structure of some of these states.

The observation of a narrow structure near the J/ψ ϕ threshold in exclusive B⁺ → J/ψ ϕ K⁺ decays produced in collisions at is reported. A signal of 19 ± 6(stat) ± 3(syst) events, with statistical significance of 5.0 standard deviations, is seen in a data sample corresponding to an integrated luminosity of 6.0 fb^-1, collected by the CDF II detector. The mass and natural width of the structure are determined to be and , consistent with the previous measurements reported as evidence of the Y(4140).

We discuss the possible interpretation of X(3872) as a DD* hadronic molecule with J^PC = 2^-+. Using the phenomenological Lagrangian approach, we studied its radiative and strong decay properties. We find that our model with about 97.6% isospin zero component explains the existing data nicely. We predict the partial widths of the radiative and strong decays of X(3872) and show that the measurement of the ratio may signal the nature of X(3872).

We report on some ideas concerning the nature of the X(3872) resonance and the need for approximately equal charged and neutral components of . Then we discuss how some hidden charm states are obtained from the interaction between vector mesons with charm and can be associated to some of the charmonium-like X,Y,Z states. Finally we discuss how the nature of these states could be investigated through different types of radiative decay.

The effects of intermediate charmed mesons on charmonium transitions with the emission of one pion or eta meson 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. Extending these considerations to the b-quark sector, we propose a new method to extract the light quark mass ratio m_u/m_d using the ϒ(4S) → h_bπ⁰(η) bottomonia transitions.

A brief review on the theoretical status of hadronic charm decays is presented. We emphasize the analyses based on the diagrammatic approach and the connection of weak annihilation with final-state rescattering. The topics on the mixing and the baryonic charm decay are sketched.

The resonant sub-structure of three-body charm meson decays can be effectively studied with Dalitz plot analyses. By using coherent sums of amplitudes, interference between different intermediate states can be described. Such interference effects can yield information on states, such as the scalar resonances, that is difficult to obtain in other ways. In this summary, we report on BABAR collaboration Dalitz plot analyses of two modes: and .

The FOCUS photoproduction experiment took data in the ninenties and produced a wealth of results in charm physics. Some of the studies were seminal for contemporary experiments, and even paved the way for the technology of many charm and beauty analysis tools.

We search for signals of Weak Annihilation in inclusive semileptonic D decays. We consider both the widths and the lepton energy moments. The analysis of Cleo data shows no clear evidence of Weak Annihilation, and allows us to put bounds on its relevance in charmless B semileptonic decays.

This is a brief review of recent lattice calculations of D semileptonic decays. This presentation includes only calculations that do not use the quenched approximation. A new state-of-the-art calculation from the HPQCD collaboration is discussed and compared with other calculations and experimental measurements.

Over 1 million charm decays were collected by the E831 photoproduction experiment (FOCUS) during the 1996–1997 Fermilab fixed target run. Analysis techniques and results particular to semileptonic and rare D and D_s charm decays from the FOCUS experiment are reviewed.

Recent calculations of the decay constants in lattice QCD are reviewed and compared to experiment.

We first review recent measurements of D → μν and D_s → μν, τν from CLEO-c. These decays are used to determine leptonic decay constants f_D and f_Ds which may be compared to modern Lattice QCD (LQCD) calculations. Such cross-checks can provide confidence in Lattice results for B_(s) meson decay constants which are needed to fully exploit data used to extract the CKM matrix elements V_ub and V_cb. We also comment briefly on the outlook for further progress at BESIII.

I present the measurements and limits of the branching fractions of leptonic decays of the D_s meson, and the subsequent estimation of the decay constant f_Ds, using the complete BaBar dataset (530 fb^-1). we measure , , , , and f_Ds = (258.6±6.4±7.5)MeV, where the first uncertainties are statistical and the second uncertainties are systematic.

I review the role of charm decays in the determination of the structure of the CKM matrix within the Standard Model, focusing on γ,|V_cd| and |V_cs|. In addition, I illustrate how these decays can be used to constrain some New Physics scenario, taking as an example the Two Higgs-Doublet Model of type II.

We review the recent measurements of rare and forbidden decays of charmed mesons at the B-factories. A preliminary result of the first measurement of orbitally excited meson radiative decay to D⁰γ final state, and the most sensitive determination of limits on the leptonic D⁰ → ℓ⁺ ℓ^- decays are briefly described.

We review the status of the standard model predictions for D-mixing and CP-violation in mixing.

Precision measurements in charm physics offer a window into a unique sector of potential New Physics interactions. LHCb is poised to become a world leading experiment for charm studies, recording enormous statistics with a detector tailored for flavor physics. This article presents recent charm CPV and mixing studies from LHCb, including LHCb's first CP asymmetry measurement with 37 pb^-1 of data collected in 2010. The difference of the CP asymmetries of D⁰ decays to the K^-K⁺ and π^-π⁺ final states is determined to be . Significant updates to the material presented at the 4^th International Workshop on Charm Physics are included.

Measurements of D⁰ meson strong-phase parameters in quantum-correlated decays by the CLEO collaboration are presented. These measurements play an important role in the determination of the unitarity triangle angle γ/ϕ₃ from B-meson decays. Measurements of the strong-phase parameters for D⁰ → K⁰π⁺π^-, D⁰ → K⁰ K⁺ K^-, D⁰ → K^- π⁺ π⁰, and D⁰ → K^- π⁺ π⁺ π^- decays are described along with their impact on the determination of γ/ϕ₃.

We report on our recent proposal to consider correlated decays to vector mesons. Thanks to the quantum and angular correlations, we show that new observables appear, that allow either to search for CP-violation or to extract the hadronic phase in D → Kπ.

We report a measurement of the CP violating asymmetry in D⁰ → π⁺π^- decays using approximately 215,000 decays reconstructed in about 5.94 fb^-1 of CDF data. We use the strong D^⋆+ → D⁰π⁺ decay ("D^⋆ tag") to identify the flavor of the charmed meson at production time and exploit CP-conserving strong pair-production in collisions. Higher statistic samples of Cabibbo-favored D⁰ → K^-π⁺ decays with and without D^⋆ tag are used to highly suppress systematic uncertainties due to detector effects. The result, A_CP(D⁰ → π⁺π^-) = [0.22 ± 0.24 (stat.) ± 0.11 (syst.)]%, is the world's most precise measurement to date and it is fully consistent with no CP violation.

Mixing and CP violation in charm meson decays provide a unique probe of possible physics beyond the standard model. In this paper, we give a brief review of the current measurements from the BABAR experiment.

More and more new charmed-strange and charmed states have been observed by experiment in the past several years. In this talk, we give a brief review of the theoretical progress of excited D/D_s mesons.

In this talk we review the vector-vector and vector-baryon interaction within the hidden gauge formalism in a coupled channel unitary approach. The vector-vector interaction is studied for all the sectors not studied before: C = 0; S = 1 (hidden-charm), C = 1, S = 1, and the flavor exotic sectors C = 1; S = -1, 2 and C = 2; S = 0, 1, 2. We find nine states, four of them in the C = 1; S = 1 sector, where one can be identified with the and it is interpreted as a D* K* molecular state. The other five resonances are found in the flavor exotic sectors C = 1; S = -1, C = 2; S = 0, 1 and can be considered as , D* D* and molecular states. In the case of the vector-baryon interaction we generate hidden charm resonances around 4.3 GeV, without or with strangeness, N*, Λ*. Nevertheless, there is not experimental evidence of such states yet.

A brief review of the excited D_s and D mesons is presented. A precision measurement of the D_s1(2536) mass and width parameters is reported by BABAR. Finally, a recent BABAR study of the Dπ and D*π final states shows first observations of the radial excitations of the D⁰, D*⁰, and D*⁺, as well as the L = 2 excited states of the D⁰ and D⁺, where L is the orbital angular momentum of the quarks.

Due to an excellent mass resolution and a large amount of available data, the CDF experiment, located at the Tevatron proton-antiproton accelerator, allows the precise measurement of spectroscopic properties, like mass and decay width, of a variety of states. This was exploited to examine the first orbital excitations of the Λ_c baryon, the resonances Λ_c(2595) and Λ_c(2625), in the decay channel , as well as the Λ_c spin excitations Σ_c(2455) and Σ_c(2520) in its decays to and final states in a data sample corresponding to an integrated luminosity of 5.2 fb^-1. We present measurements of the mass differences with respect to the Λ_c and the decay widths of these states, using significantly higher statistics than previous experiments.

Two topics are briefly reviewed in this talk: the decay of flavored hadrons or quarkonium states involving a baryon–antibaryon pair, and the spectroscopy of heavy baryons containing one, two or three heavy quarks. Some prospects for exotic heavy baryons are also discussed.

Doubly charmed mesons are studied within a quark model framework. We solve the four-quark Schordinger equation by means of a variational approach by using different interacting potentials. Our results point to the existence of a stable isoscalar doubly charmed four-quark meson with quantum numbers J^P = 1⁺.

We show that the charmonium spectrum may be reproduced to a good precision by means of a semirelativistic quark model approach based on a universal static potential effectively incorporating effects from sea quark-antiquark pairs. Detailed predictions for upcoming data are derived.

Several measurements on light hadron spectroscopy have been achieved with Beijing Spectrometry III (BESIII). BESII results such as a near threshold enhancement on the invariants mass spectrum namely X(1860) and a resonance X(1835) have been confirmed with 225 million J/ψ data accumulated from June 12, 2009 to July 28, 2009. Along with some other preliminary BESIII results including observations of X(1870), X(2120) and X(2370); the first direct measurement of a₀(980)/f₀(980) mixing; and an improved measurement on the matrix element of decay η′ → ππη have been reported at the 4th international workshop on charm physics.

We present a study of the inclusive photon spectrum from 6.3 million J/ψ decays collected with the KEDR detector at the VEPP-4M e⁺e^- collider. We measure the branching fraction of the radiative decay J/ψ → η_cγ, η_c width and mass. Taking into account an asymmetric photon line shape we obtain: M_ηc = (2978.1 ± 1.4 ± 2.0) MeV/c², Γ_ηc = (43.5 ± 5.4 ± 15.8) MeV, .

In this invited talk I discuss two recent applications of charmonium (Ψ) decays to final states, where N is a nucleon and m is a light meson. There are several motivations for studying these decays: 1) They are useful for the study of N* spectroscopy; 2) they can be used to estimate cross sections for the associated charmonium production processes , which PANDA plans to exploit in searches for charmonium hybrid exotics; and 3) they may allow the direct experimental measurement of NNm (meson-nucleon) strong couplings, which provide crucial input information for meson exchange models of the NN force. The latter two topics are considered in this talk, which will also compare results from a simple hadron pole model of these decays to recent experimental data.

With 106 million ψ′ data collected by BESIII, many new results on charmonium decays are delivered. This proceeding introduces the recent results from BESIII on this subject, including the evidence for ψ′ → γπ⁰/η, the branching ratio of χ_cJ → 4π⁰, the studies of χ_cJ → γϕ/ρ⁰/ω and χ_cJ → ωω/ϕϕ/ωϕ.

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^- → π⁺ π^- h_c at a center of mass energy of 4170 MeV.

The CHARM 2010 meeting had over 30 presentations of experimental results, plus additional future facilities talks just before this summary talk. Since there is not enough time even to summarize all that has been shown from experiments and to recognize all the memorable plots and results, this summary will give a few personal observations, an overview at a fairly high level of abstraction.

This invited summary gives some concluding remarks regarding theoretical aspects of the research presented at Charm 2010. I will specialize to the role of theory and the relative reach of theory and experiment in three of the major areas of charm physics address at this conference, specifically 1) charm production, 2) charm weak decays, and 3) charm hadron spectroscopy. After a discussion of the status of progress on representative topics in each of these areas I will conclude with a previously unrelated Feynman story from a conference in the early days of charm.