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A combined analysis of new π0 and η photoproduction data from CB-ELSA collaboration was performed including the earlier data from SAID data base, new data on beam asymmetry from the GRAAL collaboration and data on γp → KΛ and KΣ. Three baryon resonances have a substantial coupling to ηN, the well known N(1535)S11, N(1720)P13 and the newly observed N(2070)D15 resonance. A new P11 state with mass 1840 MeV and width 140 MeV was observed contributing to most of the fitted reactions. The data also demand the presence of two D13 states at 1870 and 2170 MeV. The properties of observed states and their contributions to different observables are discussed. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

We present a precision measurement of the mass of the Λc+ and studies of the production and decay of the Ωc0 and [cap_xi]c0 charm baryons using data collected by the BABAR experiment. To keep the systematic uncertainty as low as possible, the Λc+ mass measurement is performed using the low Q-value decays, Λc+ → Λ0KS0K+ and Λc+ → Σ0KS0K+. Several hadronic final states involving an Ω- and a [cap_xi]- hyperon are analyzed to reconstruct the [cap_xi]c0 and the Ωc0. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

We study the Λ(1520) resonance in a coupled channel approach involving the πΣ(1385), K[cap_xi](1530), KN and πΣ channels. Implementing unitarity in coupled channels, we make an analysis of the relative importance of the different mechanisms which contribute to the dynamical structure of this resonance. From experimental information on some partial wave amplitudes and constraints imposed by unitarity, we get a comprehensive description of the amplitudes and hence the couplings to the different channels. We test these amplitudes in different reactions like K-p → Λππ, γp → K+K-p, γp → K+π0π0Λ and π-p → K0K-p and find a fair agreement with the experimental data. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The K-p → π0π0Σ0 reaction is studied within a chiral unitary model. The distribution of π0Σ0 states forming the Λ(1405) shows, in agreement with a recent experiment, a peak at 1420 MeV and a relatively narrow width of Γ = 38 MeV. We use these data in combination with those of the π-p → K0πΣ reaction and elements of chiral unitary theory to prove that there are two Λ(1405) states instead of one as so far assumed. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

We study the mass spectrum of baryons with two and three charmed quarks. For double charm baryons the spin splitting is found to be smaller than standard quark-model potential predictions. This splitting is not influenced either by the particular form of the confining potential or by the regularization taken for the contact term of the spin-spin potential. We consistently predict the spectra for triply charmed baryons. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The studies on the light scalar mesons and excited baryon states at BES are presented, based on 5.8 × 107 J / ψ data collected with BESII detector. The measurements of some J / ψ and ηc decays are also presented in this report. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

We present the latest measurements on masses, lifetimes and branching fractions for the Bs and Bc mesons as well as for b-baryons. For the Bs meson we discuss as well the latest results on mixing. These results were produced by the CDF and D0 experiments at Fermilab or by earlier LEP and PEPII experiments. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Preliminary results from the H1 experiment on the search for the production of a candidate for the strange pentaquark in the decay channel Θ+ → Ks0p and its antiparticle in the invariant mass combinations of Ks0 mesons with protons and antiprotons in deep-inelastic ep-scattering at HERA are presented. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The extension of the periodic system into various new areas is investigated. Experiments for the synthesis of superheavy elements and the predictions of magic numbers with modern meson field theories are reviewed. Different channels of nuclear decay are discussed including cluster radioactivity, cold fission and cold multifragmentation Furthermore, we present the vacuum for the e+-e- field of QED and show how it is modified for baryons in nuclear environment. Then we discuss the possibility of producing new types of nuclear systems by implanting an antibaryon into ordinary nuclei. The structure of nuclei containing one antiproton or antilambda is investigated within the framework of a relativistic mean-field model. Self-consistent calculations predict very enhanced binding and considerable compression in such systems as compared with normal nuclei. We present arguments that the life time of such nuclei with respect to the antibaryon annihilation might be long enough for their observation. A perspective for future research is given. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

After referring to some basic features of chiral models for baryons, with quarks and mesons, we describe how to construct model states representing physical baryons. We consider soliton models such as the Linear Sigma Model or the Chromodielectric Model, and bag models such as the Cloudy Bag Model. These models are solved approximately using variational approaches whose starting point is a mean-field description. We go beyond the mean-field description by introducing quantum fluctuations in the mesonic degrees of freedom. This is achieved, in a first step, by using a quantum state to represent meson clouds and, secondly, by performing an angular momentum and isospin projection from the mean-field state (actually a coherent state). Model states for baryons (nucleon, Delta, Roper) constructed in this way are used to determine several physical properties. I this seminar we paid a particular attention to the nucleon-delta electromagnetic and weak transition, presenting the model predictions for the electromagnetic and axial amplitudes. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

A program to measure the two-pion production in nucleon-nucleon collisions exclusively and in all channels from threshold up to Tp = 1360 MeV has been started at CELSIUS-WASA. First preliminary results for ppπ+π¯ and ppπ0π0 channels are presented. In the near-threshold region they are consistent with a dominance of the Roper excitation and its successive decay into Nσ and Δπ channels. At energies Tp > 1 GeV we observe a very different behavior, which is at variance with theoretical predictions. At COSY-TOF exclusive measurements of the pp → ppπ+π¯ reaction have been carried out with polarized beam. Preliminary results show non-zero analyzing powers which point to a sizeable admixture of l ≠ 0 partial waves indicating possibly an influence of the ρ-channel. [ABSTRACT FROM AUTHOR]

By comparing SU (3)-breaking scales of linear mass formulae, it is shown that the lowest vector, axial-vector, and scalar mesons all have a qq configuration, while the ground-state octet and decuplet baryons are qqq. Also, the quark-level linear σ model is employed to predict similar qq and qqq states. Finally, the approximate mass degeneracy of the scalar a0(980) and f0(980) mesons is demonstrated to be accidental. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Using e+e- collision statistics accumulated by CLEO II.V, III detector configurations at CESR we perform Dalitz plot analyses of D-meson decays into three pseudoscalars. On this Workshop we present recently published and preliminary results of ongoing analyses of the decays, D[sup 0] → K[sub S][sup 0]π[sup +]π[sup -], D0 → π+π-π0, D[sup 0] → K[sub S][sup 0]ηπ[sup 0]. The goal of this study is to find out the leading intermediate states for each decay and to present their relative contribution in terms of complex amplitudes and relevant fit fractions. For first observed decays we measure the branching ratios. For the decays with high rate we perform a search for CP violation in terms of integrated rate, fit fractions and complex amplitude parameters. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

We compute magnetic moments of baryons with a heavy quark in the bound state approach for heavy baryons. In this approach the heavy baryon is considered as a heavy meson bound to a light baryon. The latter is represented as a soliton excitation of light meson fields. We obtain the magnetic moments by sandwiching pertinent components of the electromagnetic current operator between the bound state wave-functions. We extract this current operator from the coupling to the photon field after extending the action to be gauge invariant. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Meson-Baryon Interactions can be successfully described using both Chiral Symmetry and Unitarity. The s--wave meson-baryon scattering amplitude is analyzed in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry in the potential. Two body coupled channel unitarity is exactly preserved. The needed two particle irreducible matrix amplitude is taken from lowest order Chiral Perturbation Theory in a relativistic formalism. Off-shell behavior is parameterized in terms of low energy constants. The relation to the heavy baryon limit is discussed. The position of the complex poles in the second Riemann sheet of the scattering amplitude determine masses and widths baryonic resonances of the N(1535), N(1670), Λ(1405) and Λ(1670) resonances which compare well with accepted numbers. [ABSTRACT FROM AUTHOR]

Sufficiently fast chemical equilibration of (strange) antibaryons in an environment of nucleons, pions and kaons during the course of a relativistic heavy ion collision can be understood by a 'clustering' of mesons to buildt up baryon-antibaryon palrs. This multi-mesonic (fusion-type) process has to exist in medium due to the principle of detailed balance. Novel numerical calculations for a dynamical setup are presented. They show that - at maximum SPS energies - yields of each antihyperon specie are obtained which are consistent with chemical saturated populations of T ≈ 150 -- 160 MeV, in line with popular chemical freeze-out parameters extracted from thermal model analyses. [ABSTRACT FROM AUTHOR]

It is interesting that the fields of meson and baryon spectroscopy have taken divergent paths in the last decade. It is time the fields were more aware of the similarities and this author hopes the fields will benefit from each other's accomplishments. This note will point out the similarities and the differences. Sometimes, the differences are in nomenclature. However, there are also practical reasons for the divergences. The typical meson experiment has a more complicated final state than baryon experiments and the most complete theoretical treatments limit the number of final state particles to three. There are also important differences in sociology. [ABSTRACT FROM AUTHOR]

The relativistic string with massive ends describing the meson and four various string baryon models (quark-diquark, linear, three-string and triangle) are considered. For all these systems the rotational motions or planar uniform rotations are used for describing orbitally excited hadron states on the Regge trajectories. We analyze small disturbances of these rotations (quasirotational states) with different methods. This study demonstrates that the classical rotational motions for the meson-like model and the triangle string baryon model are stable, but they are unstable for the linear configuration (q-q-q) and for the three-string (Y). For the latter two models the spectrum of the quasirotational oscillations contains exponentially growing modes. But for the string with massive ends we have two types of these modes describing stationary waves without growth. The obtained quasirotational states are useful for quantization and describing higher radial hadron excitations. [ABSTRACT FROM AUTHOR]

Narrow low mass exotic hadronic structures were recently observed in mesons, baryons and dibaryons. Narrow mesons, in the mass range 300 ≤ M ≤ 750 MeV, were observed using the pp → ppX reaction. Narrow baryons in the mass range 1000≤M≤ 1400 MeV were observed using the pp → pπ[sup +]X and dp → ppX reactions. The statistical significances of these structures vary up to 4.6 standard deviations (S.D.) for mesons and up to 16.9 S.D. for baryons. These exotic states are associated with precursor quark deconfinement. [ABSTRACT FROM AUTHOR]

Coherent π[sup +]&pi[sup -]π[sup -] production in the interactions of a beam of 600 GeV π[sup -] mesons with C, Cu and Pb nuclei has been studied with the SELEX facility (Experiment E781 at Fermilab). The a[sub 2] (1320) meson signal has been detected in the Coulomb (low q[sup 2]) region. The Primakoff formalism used to extract radiative decay width of this meson yields F = 284 ± 25 ± 25 keV, which is the most precise measurement to date. [ABSTRACT FROM AUTHOR]

The I=1 and I=0 kaon-nucleon s, p, d, f, g-waves phase shifts have been calculated in a non relativistic quark potential model using the resonating group method (RGM). The interquark potential includes gluon exchanges with a spin-orbit interaction. This force was determined to reproduce as well as possible the meson and baryon spectra. The same force is employed for the cluster and intercluster dynamics and the relative KN wave function is calculated without any approximation. While some channels are correctly described, the theory is still unable to explain others. [ABSTRACT FROM AUTHOR]

Progress in computing the spectrum of excited baryons and mesons in lattice QCD is described. Large sets of spatially-extended hadron operators are used. The need for multi-hadron operators in addition to single-hadron operators is emphasized, necessitating the use of a new stochastic treatment of the low-lying modes of quark propagation which exploits Laplacian Heaviside quark-field smearing. A new glueball operator is tested and computing the mixing of this glueball operator with a quark-antiquark operator and multiple two-pion operators is shown to be feasible. [ABSTRACT FROM AUTHOR]

A significant amount of experimental data for particle production in high-energy heavy ion collisions (10 - 200 GeV/A at center of mass) has been accumulated during last years. Many different theoretical attempts have tried to describe these data using thermal models in the approximation of global thermal equilibrium considering only one freeze-out temperature. However the thermal models often are not able to describe adequately the whole multiplicities of hadrons. For instance, the abundance of strange particles is overestimate and the pion yields are underestimated. In this work is presented a thermal hadronic model with two different temperatures in order to describe the baryonic and mesonic chemical freeze-out in ultra-relativistic heavy ion collisions. The model is used to fit the particle population ratios of the hadrons produced in the reaction. The proposal is not merely to incorporate one additional degree of freedom in the adjustment procedure of data, but to present and alternative scenario for the freeze out stage in the collisional proces s. This new reformulated version of thermal model was applied to a set of data, offering a rather good improvement in the fitting of the calculated particle ratios to the data. The results suggest that the introduced model makes the thermal approach more robust to handle with a larger number of colliding systems and a more comprehensive set of reaction observables. [ABSTRACT FROM AUTHOR]

The internal structure of the resonant Λ(1405) state is investigated based on meson-baryon coupled-channels chiral dynamics, by evaluating density distributions obtained from the form factors of the Λ(1405) state. The form factors are extracted from current-coupled scattering amplitudes in which the current is coupled to the constituent hadrons inside Λ(1405). Using several probe interactions and channel decomposition, we find that the resonant Λ(1405) state is dominantly composed of widely spread K around N, with a small fraction of the escaping πΣ component. [ABSTRACT FROM AUTHOR]

The constituent quark number scaling of elliptic flow is studied in a non-equilibrium hadronization and freeze-out model with rapid dynamical transition from ideal, deconfined and chirally symmetric Quark Gluon Plasma, to final non-interacting hadrons. In this transition a Bag model of constituent quarks is considered, where the quarks gain constituent quark mass while the background Bag-field breaks up and vanishes. The constituent quarks then recombine into simplified hadron states, while chemical, thermal and flow equilibrium break down one after the other. In this scenario the resulting temperatures and flow velocities of baryons and mesons are different. Using a simplified few source model of the elliptic flow, we are able to reproduce the constituent quark number scaling, with assumptions on the details of the non-equilibrium processes. [ABSTRACT FROM AUTHOR]

Meson resonances are linear combinations of qq and meson-meson (MM) baryon resonances are combinations of qqq and meson-baryon. Mixing between these combinations arises via decays of confined states to meson-meson or meson-baryon. There is a useful analogy with the covalent bond in molecular physics. One eigenstate is lowered by the mixing. Cusps arise at thresholds. At sharp thresholds due to S-wave 2-particle decays, these cusps play a conspicuous role in many sets of data. [ABSTRACT FROM AUTHOR]

The study of the properties of baryon resonances can provide us with hints to help us understand the structure of non-perturbative QCD and the effect of a particular resonance on polarization observables. The investigation of double-pion photoproduction data is needed to discover higher-lying states and their properties at and above W ≈ 1.8 GeV. Therefore, the analysis of the helicity difference in gp γp→pπ+π- will help us in our understanding of QCD. The CLAS g9a (FROST) experiment, as part of the N* spectroscopy program at Jefferson Laboratory, has accumulated photoproduction data using linearly and circularly polarized photons incident on a longitudinally-polarized butanol target in the photon energy range 0.3 to 2.4 GeV. The FROST experiment provides an important step toward a “complete” experiment for the reaction γN→KY. In this contribution, the method to calculate the helicity difference for the reaction γp→pπ+π- will be described and preliminary results will be discussed. [ABSTRACT FROM AUTHOR]

Six-quark dibaryon model for fundamental NN- and 3N-forces at intermediate and short ranges are discussed briefly. The structure of the intermediate dibaryon dressed with σ-meson field is similar to those of Roper resonance where the σ-meson field plays a very important role. The t-channel σ-exchange between dibaryon and third nucleon is shown to result in new strong scalar attractive 3N force which contributes at least a half of nuclear binding in 3N system. This dibaryon induced σ-exchange leads also to a new spin-orbit attractive 3N-force. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Using a chiral unitary approach for meson-baryon scattering in the strangeness zero sector, where the N*(1535) and Δ*(1700) resonances are dynamically generated, we study the reactions γp → π0ηp and γp → π0K0Σ+ at photon energies at which the final states are produced close to threshold. Among several reaction mechanisms, we find the most important is the excitation of the Δ*(1700) state which subsequently decays into a pseudoscalar meson and the N*(1535). Hence, the reaction provides useful information with which to test current theories of the dynamical generation of the low-lying 1/2- and 3/2- states. Predictions are made for cross sections and invariant mass distributions which can be compared with forthcoming experiments at ELSA. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The SELEX Fixed Target Experiment (Fermilab E781) employs beams of Σ-, pions and protons to study the production and decay properties of charmed Mesons and Baryons. Here we present recent results on doubly-charmed baryons and charmed-strange mesons. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The Yang-Mills Schrödinger equation is solved in Coulomb gauge for the vacuum by the variational principle using an ansatz for the wave functional, which is strongly peaked at the Gribov horizon. We find an infrared suppressed gluon propagator, an infrared singular ghost propagator and an almost linearly rising confinement potential. Using these solutions we calculate the eletric field of static color charge distributions relevant for mesons and baryons. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

We study two distinct phases of nuclear matter, a baryon-meson phase and a quark-gluon phase (QGP). For the baryon-meson phase we develop an equation of state (EoS) using a quark-meson formulation based on a new version of the fuzzy bag model with scalar-isoscalar, vector-isoscalar and vector-isovector meson-quark couplings and leptonic degrees of freedom as well as the constraints of chemical equilibrium, baryon number and electric charge conservation. For the QGP phase we model an EoS for asymptotically free massless quarks and gluons using the MIT approach and a temperature and baryon chemical potential dependent bag constant, B(T,μ), which allows an isentropic equilibrium phase transition from a QGP to a hadron gas. Our main results indicate the EoS and static global properties of neutron stars and protoneutron stars at low and moderate values of temperature are slightly modified in comparison to the predictions based on the MIT bag model with a constant B. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]