Different variants of the physical QCD{sub 2} are analyzed. The role of the chiral background field in the theory is stressed. A massive bound state creating operator in the massless physical QCD{sub 2} is constructed.

An approach to realize a hyperon as a bound-state of a two-flavor baryon and a kaon is considered in the context of the Sakai�Sugimoto model of holographic QCD, which approach has been known in the Skyrme model as the bound-state approach to strangeness. As a simple case of study, pseudo-scalar kaon is considered as fluctuation ...

Deep-inelastic diffractive scaling violations have provided fundamental insight into the QCD pomeron, suggesting a single gluon inner structure rather than that of a perturbative two-gluon bound state. This talk outlines a derivation of a high-energy, tra...

We compare the results of a numerical lattice QCD calculation of the charmonium spectrum with the structure of a general nonrelativistic potential model. To achieve this we form the nonrelativistic reduction of derivative-based fermion bilinear interpolating fields used in lattice QCD calculations and compute their overlap with cc meson ...

Two-loop energy densities of color ferromagnetic states are obtained using the beta -function calculated to two-loop approximation and the exact formula for the energy density of such a state. This is used to derive bounds on the MIT bag constant correcti...

The systematic approach to study bound states in quantum chromodynamics is presented. The method utilizes nonperturbative flow equations in the confining background, that makes possible to perform perturbative renormalization and to bring the QCD Hamiltonian to a block-diagonal form with the number of quasiparticles conserving in each ...

We present a new technique for analyzing heavy-quark bound states in lattice QCD. The method is based upon a nonrelativistic reformulation of the heavy-quark dynamics that is systematically developed starting from the Dirac theory. It is far superior to traditional relativistic techniques, as we illustrate in a numerical study of the ...

The velocity nonrelativistic QCD Lagrangian for colored heavy scalar fields in the fundamental representation of QCD and the renormalization group analysis of the corresponding operators are presented. The results are an important ingredient for renormalization group improved computations of scalar-antiscalar bound ...

Central exclusive production (CEP) processes in high-energy hadron collisions offer a very promising framework for studying both novel aspects of QCD and new physics signals. We report on the results of a theoretical study of the CEP of heavy quarkonia (? and ?) at the Tevatron, RHIC and LHC (see for details [1]-[3]). These processes provide important information on the ...

Encouraged by recent developments in AdS/QCD models for the light quark system, we study heavy quarkonium in the framework of the AdS/QCD models. We calculate the masses of cc vector meson states using the AdS/QCD models at zero and at finite temperature. Among the models adopted in this work, we find that the ...

Continuum strong QCD is the application of models and continuum quantum field theory to the study of phenomena in hadronic physics, which includes; e.g., the spectrum of QCD bound states and their interactions. Herein the author provides a Dyson-Schwinger equation perspective, focusing on qualitative aspects of ...

The Lorentz nature of the effective interquark interaction is investigated in a heavy-light quarkonium. The approach of the Dyson-Schwinger-type equation and the quantum-mechanical Hamiltonian method of the QCD string with quarks at the ends are employed to demonstrate that the effective scalar interaction, which appears owing to chiral-symmetry breaking, is responsible for ...

A model for the QCD ground state is proposed which implements a confinement mechanism, leading to color confinement with a definite set of bound state equations. It has lower energy than the perturbative vacuum and is stable against color magnetic fields produced by vacuum fluctuations. It consists of a coherent ...

We review a recently developed relativistic quark-antiquark bound state equation using the expansion in intermediate states. Using a QCD motivated potential we succeeded very well to fit both the heavy systems (b anti b, c anti c) and the light systems (s...

The discussion covers quarks as we know them, the classification of ordinary mesons in terms of constituent quarks, hidden charm states and charmed mesons, bottom quarks, positronium as a model for quarti q, quantum chromodynamics and its foundation in ex...

It is expected from quantum chromodynamics (QCD) that glueballs, bound states which contain gluons but no valence quarks, should exist. To date, no conclusive evidence for glueballs has been presented. After a brief review of the expected properties and experimental signatures of glueballs the status of some glueball candidate ...

We calculate helicity amplitudes and decay rates for Zweig-forbidden radiative decays of a exp 3 S sub 1 (Qanti Q) bound state into exp 1 S sub 0 (qanti q) and exp 3 Psub(J)(qanti q) states in lowest order QCD. We employ a new technique of scalarizing loo...

A central focus of QCD studies is the non-perturbative structure of hadron wavefunctions, not only bound-state valence quark distributions, but also the intrinsic gluon and heavy quark distributions associated with higher Fock states. In this talk I discuss how the production of heavy quark systems and the use of nuclear targets can ...

A natural calculus for describing the bound-state structure of relativistic composite systems in quantum field theory is the light-front Fock expansion which encodes the properties of a hadrons in terms of a set of frame-independent $n-$particle wavefunct...

We present a framework for deep inelastic scattering, with bound state properties in accordance with a QCD force field acting like a vortex line in a colour superconducting vacuum, which implies some simple coherence effects. Within this scheme one may de...

We discuss the light-cone quantization of gauge theories from two perspectives: as a calculational tool for representing hadrons as QCD bound-states of relativistic quarks and gluons, and also as a novel method for simulating quantum field theory on a com...

Early scattering experiments revealed that the proton was not a point particle but a bound state of many quarks and gluons. Deep inelastic scattering (DIS) experiments have accurately determined the probability of struck quarks carrying a fraction of the ...

We compare the results of a numerical lattice QCD calculation of the charmonium spectrum with the structure of a general non-relativistic potential model. To achieve this we form the non-relativistic reduction of derivative-based fermion bilinear interpolating fields used in lattice QCD calculations and compute their overlap with $c\\bar{c}$ meson ...

We present results on heavy quark free energies in 2-flavour QCD. The temperature dependence of the interaction between static quark anti-quark pairs will be analyzed in terms of temperature dependent screening radii, which give a first estimate on the medium modification of (heavy quark) bound states in the quark gluon plasma. ...

The light-cone Fock representation encodes the bound-state quark and gluon properties of hadrons, including their helicity and flavor correlations, in terms of universal process-independent and frame-independent wavefunctions. It also provides a physical factorization scheme for separating hard and soft contributions in both exclusive and inclusive hard processes. A new type ...

We investigate the residual chromomagnetic nonperturbative interaction between colour sources which survives above the deconfinement temperature. This interaction is demonstrated to be attractive enough to support bound states of quarks (and gluons). Although, for heavy quarks, such bound states appear to be very ...

As a test of quantum chromodynamics (QCD), we suggest looking for gluon jets in the decay of a heavy quark-antiquark bound state produced in e exp + e exp - -annihilation, Q anti Q implies 3 gluons implies 3 gluon jets. In particular, we point out that th...

We present results on heavy quark free energies in 2-flavour QCD. The temperature dependence of the interaction between static quark anti-quark pairs will be analyzed in terms of temperature dependent screening radii, which give a first estimate on the me...

We discuss the renormalization of the contour dependent gauge invariant composite bilocal or string operator q-bar(2) exp Vertical Barg integ sub 12 A dzVertical Bar q(1) in QCD, which one would naturally associate with the hadronic bound states. We then ...

We describe the application of Dyson-Schwinger equations to the calculation of hadron observable. The studies at zero temperature (T) and quark chemical potential ({mu}) provide a springboard for the extension to finite-(T, {mu}). Our exemplars highlight that much of hadronic physics can be understood as simply a manifestation of the nonperturbative, momentum-dependent dressing of the elementary ...

Light-meson mass formulas are derived from QCD spin-dependent forces and various masses are predicted in the quarkonium-model picture. Except for ..pi..(135) and theta(1640), all the meson spectra can be accounted for as bound states of quark-antiquark pair but the large deviations between the observed and predicted values of ...

The cross section for the reaction e + e ??3S1+1S0 is calculated in the framework of perturbative QCD, using the nonrelativistic approximation for the3S1 and1S0 bound states. The model is applied to J/? plus ?, ?, ?', and l production. We find extremely small rates in contrast to previous estimates based on vector meson dominance and ...

The authors write the 4-point Green function in QCD in the Feynman-Schwinger representation and show that all the dynamical information are contained in the Wilson loop average. They work out the QED case in order to obtain the usual Bethe-Salpeter kernel. Finally they discuss the QCD case in the non-perturbative regime giving some insight in the nature of ...

Early scattering experiments revealed that the proton was not a point particle but a bound state of many quarks and gluons. Deep inelastic scattering (DIS) experiments have accurately determined the probability of struck quarks carrying a fraction of the proton's momentum. The current generation of experiments and Lattice QCD ...

Early scattering experiments revealed that the proton was not a point particle but a bound state of many quarks and gluons. Deep inelastic scattering (DIS) experiments have accurately determined the probability of struck quarks carrying a fraction of the proton's momentum. The current generation of experiments and Lattice QCD ...

Deep-inelastic diffractive scaling violations have provided fundamental insight into the QCD pomeron, suggesting a single gluon inner structure rather than that of a perturbative two-gluon bound state. This talk outlines a derivation of a high-energy, transverse momentum cut-off, confining solution of QCD. The ...

We outline a connection between scalar quark confinement, a phenomenologically successful concept heretofore lacking fundamental justification, and QCD. Although scalar confinement does not follow from QCD, there is an interesting and close relationship between them. We develop a simple model intermediate between scalar confinement and the ...

A model of broken QCD is described here; SU/sub 3//sup c/ is broken to SO/sub 3//sup g/ (g for glow) such that color triplets become glow triplets. With this breaking pattern, there should exist low-mass, fractionally-charged diquark states that are not strongly bound to nuclei, but are rarely produced at present accelerator ...

The relationship of the quark model to the known chiral properties of QCD is a long-standing problem in the interpretation of low-energy QCD. In particular, how can the pion be viewed as both a collective Goldstone-boson quasiparticle and as a valence-quark-antiquark bound state? A comparison of the many-body ...

We explore the possibility that weakly interacting dark matter can form bound states--WIMPonium. Such states are expected in a wide class of models of particle dark matter, including some limits of the minimal supersymmetric standard model. We examine the conditions under which we expect bound ...

Using a simple relativistic QFT model of scalar fields we demonstrate that the analytic confinement (propagator is an entire function in the complex p2-plane) and the weak coupling constant lead to the Regge behaviour of the two-particle bound states. In QCD we assume that the gluon vacuum is realized by the self-dual homogeneous ...

In the Standard Model (SM) of particle physics, quarks are permanently confined by the strong interaction into bound states called hadrons. The values of some parameters, such as the quark masses and the strengths of the decays of one quark flavour into another, cannot be measured directly and must be deduced from experiments on hadrons. This requires ...

The application of perturbative quantum chromodynamics to the dynamics of hadrons at short distance is reviewed, with particular emphasis on the role of the hadronic bound state. A number of new applications are discussed, including the modification to QCD scaling violations in structure functions due to hadronic binding; a discussion ...

The author presents a method for solving the quark-antiquark bound state problem using the Bethe-Salpeter equation. They reduce the Bethe-Salpeter equation to a form which allows the numerical evaluation of the mass spectrum. They find good agreement with the data for b anti b and c anti c systems. The theoretical disagreement for lighter quark systems ...

We present a method for solving the quark-antiquark bound state problem using the Bethe-Salpeter equation. We reduce the Bethe-Salpeter equation to a form which allows the numerical evaluation of the mass spectrum. We find good agreement with the data for b | b and c| c systems. The theoretical disagreement for lighter quark systems raises some fundamental ...

Charmonium, the set of bound states of a charmed quark and its antiquark, have provided considerable insight into the strong forces between quarks and antiquarks. Furthermore, improved nonperturbative QCD inspired phenomenological potential function calculations may allow extraction of a very accurate value of ..cap alpha../sub s/ ...

Within the framework of a holographic dual model of QCD, we develop a formalism for calculating form factors of vector mesons. We show that the holographic bound states can be described not only in terms of eigenfunctions of the equation of motion, but also in terms of conjugate wave functions that are close analogues of ...

We develop a Rayleigh-Ritz variational method for estimating relativistic, multi-particle bound state energies in any (weak-coupling) quantum field theory. A comparison is made with bound state energies derived from the Bethe-Salpeter equation in the Wick-Cutkosky model. Possible applications to ...

We analyze the free energy of a static quark-antiquark pair in quenched QCD at short and large distances. From this we deduce running couplings, g{sup 2} (r, T), and determine the length scale that separates at high temperature the short distance perturbative regime from the large distance nonperturbative regime in the QCD plasma phase. Ambiguities in the ...

The Standard Model (SM) of elementary particles, in terms of quarks and leptons, is in good agreement with experimental observations. But unlike the leptons, quarks do not exist in free states. They are instead tightly bound in hadrons, which consist of mesons and baryons, which are themselves quark-antiquark states and 3-quark ...

We introduce a generalization of 1+1 dimensional large N{sub c} QCD, which we refer to as ''reduced'' QCD, or rQCD. In this model gluons and quark momenta live in 1+1 dimensions only, but the quark spin and all other particles (leptons, and the photon) live in the full 1 + 3 dimensions. The ...

We present evidence for the existence of a bound H dibaryon, an I=0, J=0, s=-2 state with valence quark structure uuddss, at a pion mass of m(?)?389??MeV. Using the results of lattice QCD calculations performed on four ensembles of anisotropic clover gauge-field configurations, with spatial extents of L?2.0, 2.5, 3.0, and 3.9 fm at a ...

We present evidence for the existence of a bound H dibaryon, an I=0, J=0, s=-2 state with valence quark structure uuddss, at a pion mass of m?�389MeV. Using the results of lattice QCD calculations performed on four ensembles of anisotropic clover gauge-field configurations, with spatial extents of &Ltilde;2.0, 2.5, 3.0, and 3.9 ...

We analyse the extraction of the bound-state form factor from vacuum-to-hadron correlator, which is the basic object for the calculation of hadron form factors in the method of light-cone sum rules in QCD. We study this correlator in quantum mechanics, calculate it exactly, and derive the corresponding OPE. We then apply the standard procedures of ...

We study the accuracy of the bound-state parameters obtained with the method of dispersive sum rules, one of the most popular theoretical approaches in nonperturbative QCD and hadron physics. We make use of a quantum-mechanical potential model since it provides the only possibility to probe the reliability and the accuracy of this method: one obtains the ...

The quantization of gauge theory at fixed light-cone time {tau} = t - z/c provides new perspectives for solving non-perturbative problems in quantum chromodynamics. The light-cone Fock state expansion provides both a precise definition of the relativistic wavefunctions of hadrons as bound-states of quarks and gluons and a general calculus for predicting ...

A relativistic quantum-field model based on analytical confinement is developed to build stable bound states of spin-half and spin-one particles. The spectra of two-quark ground states are defined by using the ladder Bethe-Salpeter equation. An analytic expression for the running coupling in QCD is obtained that ...

Casher and Susskind have noted that in the light-front description, spontaneous chiral symmetry breaking in quantum chromodynamics (QCD) is a property of hadronic wavefunctions and not of the vacuum. Here we show from several physical perspectives that, because of color confinement, quark and gluon QCD condensates are associated with the internal dynamics ...

The nonrelativistic baryon gas of QCD[sub 1+1] for SU(2) color is studied in the low density regime using two complementary approaches: In the classical limit, the Gibbs free energy can be evaluated analytically, yielding an exact value for the second virial coefficient and a bound for the equation of state at higher densities. Certain ...

In the deconfinement phase of QCD, quarks and gluons interact with the dense stochastic color-magnetic vacuum. We consider the dynamics of quarks in this deconfinement phase using the field correlators method and derive an effective nonperturbative interquark potential, in addition to the usual perturbative short-range interaction. We find the resulting ...

Exclusive two-photon processes at large momentum transfer, particularly Compton scattering {gamma}p{yields}{gamma}p and its crossed-channel reactions {gamma}{gamma}{yields}{bar p}p and {bar p}p{yields}{gamma}{gamma}, can provide definitive information on the bound-state distributions of quarks in hadrons at the amplitude level. Recent theoretical work has shown that ...

Determinations of the gluon propagator in the continuum and in lattice simulations are compared. A systematic truncation procedure for the quark Dyson-Schwinger and bound state Bethe-Salpeter equations is described. The procedure ensures the flavor-octet axial- vector Ward identity is satisfied order-by-order, thereby guaranteeing the preservation of ...

The QCD {beta} function and the anomalous dimensions for the Coulomb potential and the static potential first differ at three loop order. We evaluate the three loop ultrasoft anomalous dimension for the Coulomb potential and give the complete three loop running. Using this result, we calculate the leading logarithmic Lamb shift for a heavy-quark{endash}antiquark ...

We determine viscosity corrections to the retarded, advanced and symmetric gluon self-energies and to the static propagator in the weak-coupling ''hard loop'' approximation to high-temperature QCD. We apply these results to calculate the imaginary part of the heavy-quark potential which is found to be smaller (in magnitude) than at vanishing ...

We analytically show that mesonic bound states of confined monopoles appear inside a non-Abelian vortex string in massless three-flavor QCD at large quark chemical potential ?. The orientational modes CP2 in the internal space of a vortex is described by the low-energy effective world-sheet theory. Mesons of confined monopoles are ...

In the heavy quark limit of Coulomb gauge QCD and by truncating the Yang-Mills sector to include only dressed two-point functions, an analytic nonperturbative solution to the Faddeev equation for three-quark bound states in the case of equal quark separations is presented. A direct connection between the temporal gluon propagator and ...

Bosonic string formation in gauge theories is reviewed with particular attention to the confining flux in lattice QCD and its effective string theory description. Recent results on the Casimir energy of the ground state and the string excitation spectrum are analyzed in the Dirichlet string limit of large separation between static sources. The closed ...

We estimate the QCD effective charge {alpha}{sub s} in the low-energy region by exploiting the conventional meson spectrum within a relativistic quantum-field model based on analytic confinement. The ladder Bethe-Salpeter equation is solved for the masses of two-quark bound states. We found a new, independent, and specific ...

A systematic procedure to consistently formulate a field theoretical, QCD bound state problem with a fixed number of constituents is outlined. The approach entails applying the Hamiltonian flow equations, which are a set of continuous unitary transformations, to a QCD motivated Hamiltonian with a confining ...

We consider bound states of a meson and a baryon (meson and antibaryon) in lattice QCD in a Euclidean formulation. For simplicity, considering the + parity sector we analyze an SU(3) theory with a single flavor in 2+1 dimensions and two-dimensional Dirac matrices. We work in the strong coupling regime, i.e., in a region of parameters ...

Continuum strong QCD is the application of models and continuum quantum field theory to the study of phenomena in hadronic physics, which includes; e.g., the spectrum of QCD bound states and their interactions; and the transition to, and properties of, a quark gluon plasma. We provide a contemporary perspective, ...

Quantum chromodynamics provides a fundamental description of hadronic and nuclear structure and dynamics in terms of elementary quark and gluon degrees of freedom. In practice, the direct application of QCD to reactions involving the structure of hadrons is extremely complex because of the interplay of nonperturbative effects such as color confinement and multi-quark ...

The Dyson-Schwinger equations (DSEs) are a tower of coupled integral equations that relate the Green functions of QCD to one another and include the equation for the quark self-energy, the analogue of the gap equation in superconductivity; the Bethe-Salpeter equation, the solution of which yields meson bound state amplitudes; and the ...

We calculate mass shift of the J/? meson in nuclear matter arising from the modification of DD, DD* and D*D* meson loop contributions to the J/? self-energy. The estimate includes the in-medium D and D* meson masses consistently. The J/? mass shift (scalar potential) calculated is negative (attractive), and is complementary to the attractive potential obtained from the QCD ...

The light-front quantization of gauge theories in light-cone gauge provides a frame-independent wavefunction representation of relativistic bound states, simple forms for current matrix elements, explicit unitarity, and a Fock space built on a trivial vacuum. The AdS/CFT correspondence has led to important insights into the properties of quantum ...

The effective QCD charge extracted from {tau} decay is remarkably constant at small momenta, implying the near-conformal behavior of hadronic interactions at small momentum transfer. The correspondence of large-N{sub c} supergravity theory in higher-dimensional anti-de Sitter spaces with gauge theory in physical space-time also has interesting implications for hadron ...

In the past decade, lattice QCD has been able to compute the low-lying glueball spectrum with accuracy. Like other effective approaches of QCD, potential models still have difficulties to cope with gluonic hadrons. Assuming that glueballs are bound states of valence gluons with zero current mass, it is readily ...

A review is given to pentaquark mass predictions in quark models and QCD. It is pointed out that no successful quark model prediction is available for low-lying pentaquark states. Some new results of direct application of QCD, QCD sum rules and lattice QCD, are also presented.

We analyze the possible existence of nonperturbative contributions in heavy Q�Q systems (Q� and Q need not have the same flavor) which cannot be expressed in terms of local condensates. Starting from QCD, with well-defined approximations and splitting properly the fields into large and small momentum components, we derive an effective Lagrangian where hard gluons (in the ...

The zeta-family of bound states, formed by the anticipated t-quark and its antiquark, is discussed. The quantitative connection between the zeta-spectroscopy and the short distance behavior of the quark-antiquark potential is examined. It is pointed out that the next quarkonium system will lead to an accurate determination of the QCD ...

A novel procedure for extracting hadron characteristics from QCD sum rules, based on effective continuum thresholds (necessary for the implementation of quark-hadron duality) which may depend on the involved momenta and on the Borel parameter(s), enables us to quantify the uncertainties induced by the quark-hadron duality approximation and to achieve a significantly higher ...

The decay widths of top quark to S-wave bc and bb bound states are evaluated at the next-to-leading-order accuracy in strong interaction. Numerical calculation shows that the next-to-leading-order corrections to these processes are remarkable. The QCD renormalization scale dependence of the results is obviously depressed, and hence the ...

The spontaneous breakdown of chiral symmetry is analyzed dynamically via bound-state Bethe-Salpeter equations. While in general spontaneous mass generation is linked to a massless 0/sup -/ pion and no specific constraint on a massive 0/sup +/ meson, for the particular theory of asymptotically free QCD it is shown that a 0/sup +/ sigma meson should exist ...

GastineauBlanquierAichelin, , however, the meson states they consider are still bound for temperatures greater than the deconfinement temperature Tc . On the other hand, our model deals with unconfined quarks and includes a description of the q q� resonances found in lattice QCD studies that make use of the maximum entropy method. ...

We calculate the scattering lengths of the scattering processes where one or both hadrons contain charm quarks in full lattice QCD. We use relativistic Fermilab formulation for the charm quark. For the light quark, we use domain-wall fermions in the valence sector and improved Kogut- Susskind sea quarks. In J = Psi - N and D - K channels, we observe attractive interactions. ...

The correlation between baryon number and strangeness elucidates the nature of strongly interacting matter. This diagnostic can be extracted theoretically from lattice QCD calculations and experimentally from event-by-event fluctuations. The analysis of present lattice results above the critical temperature severely limits the presence of q{bar q} bound ...

The light-front quantization of gauge theories in light-cone gauge provides a frame-independent wavefunction representation of relativistic bound states, simple forms for current matrix elements, explicit unitarity, and a Fock space built on a trival vacu...

QCD IGOR SHOVKOVY \\Lambday Physics Department, University of Cincinnati Cincinnati, Ohio 45221 of the corresponding bound states whose binding energy is small compared to the value of the quark mass. The detailed get broken, and an extra NG boson and a pseudo�NG boson appear in the low energy spectrum. They both

We show that for strong enough Yukawa coupling the electroweak standard-model quark finds it energetically advantageous to transform itself into a bound state in a Skyrme background. This picture implies a maximum mass for the quark and predicts the existence of an excited spin-(3/2 quark. Moreover, two-quark, color-antitriplet, and three-quark, ...

Light scalar-quarks {phi} (colored scalar particles or idealized diquarks) and their color-singlet hadronic states are studied with quenched SU(3)c lattice QCD in terms of mass generation. We investigate 'scalar-quark mesons' {phi}{dagger}{phi} and 'scalar-quark baryons' {phi}{phi}{phi} as the bound ...

Using a simple relativistic QFT model of scalar fields we demonstrate that the analytic confinement (propagator is an entire function in the complex p{sup 2} plane) and the weak coupling constant lead to the Regge behavior of the two-particle bound states. In QCD we assume that the gluon vacuum is realized by the self-dual homogeneous ...

We study effective SU(2) gauge field actions that include bound-state contributions from the fermion determinant. Drawing on an analogy with polymers, we construct polaron-extrema--instanton--anti-instanton structures bound by localized fermion-antifermion pairs. We argue that they are the relevant ones when massless fermions are present. As a check on our ...

Casher and Susskind [Casher A, Susskind L (1974) Phys Rev 9:436�460] have noted that in the light-front description, spontaneous chiral symmetry breaking is a property of hadronic wavefunctions and not of the vacuum. Here we show from several physical perspectives that, because of color confinement, quark and gluon condensates in quantum chromodynamics (QCD) are associated ...

The combination of Anti-de Sitter space (AdS) methods with light-front holography leads to a semi-classical first approximation to the spectrum and wavefunctions of meson and baryon light-quark bound states. Starting from the bound-state Hamiltonian equation of motion in QCD, we derive relativistic light-front wave ...

Heavy quark systems and glueball candidates, the particles which are relevant to testing QCD, are discussed. The review begins with the heaviest spectroscopically observed quarks, the b anti-b bound states, including the chi state masses, spins, and hadronic widths and the non-relativistic potential models. Also, P ...

AdS/QCD, the correspondence between theories in a dilaton-modified five-dimensional anti-de Sitter space and confining field theories in physical space-time, provides a remarkable semiclassical model for hadron physics. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical ...

The AdS/CFT correspondence has led to important insights into the properties of quantum chromodynamics even though QCD is a broken conformal theory. We have recently shown how a holographic model based on a truncated AdS space can be used to obtain the hadronic spectrum of light q{bar q}, qqq and gg bound states. Specific hadrons are ...

One of the most challenging open problems in heavy quarkonium physics is the double charm production in e+e- annihilation at B factories. The measured cross section of e+e- --> J/psi + eta(c) is much larger than leading order (LO) theoretical predictions. With the nonrelativistic QCD factorization formalism, we calculate the next-to-leading order (NLO) ...

It is known, since the 70s, that the large N 't Hooft limit of gauge theories is related to string theories. In 1998, J. M. Maldacena identified precisely such a relation: the so-called AdS/CFT correspondence which speculates a duality between a large N strongly-coupled supersymmetric and conformal Yang-Mills theory in four dimensions and a weakly-coupled string theory defined in a ...

Gribov's theory of light quark confinement implies the existence of two kinds of scalar bound states. The phase diagram of the three-flavor QCD is mapped out in the (m? - mK)-plane with help of the SUL(3) � SUR(3) linear sigma model supplemented with the assumption that the masses of the so-called superbound scalars do not change ...

The recent discovery of deeply bound pionic states in heavy nuclei, using pion transfer reactions of the type 206Pb (d,3He) ?- ? 205Pb is reviewed. Binding energies and widths of pionic 1s- and 2p- states are determined for 207Pb and recently also 205Pb. The characteristic narrowness of these states, generated by a ...

One can distinguish two types of contributions to the quark and gluon structure functions of hadrons in quantum chromodynamics: intrinsic'' contributions, which are due to the direct scattering on the bound-state constituents, and extrinsic'' contributions, which are derived from particles created in the collision. In this talk, I ...

A summary of new experimental results and recent theoretical developments discussed in the 'Hadronic Final States and QCD' working group is presented.

In this article, we perform a detailed study of the mass spectrum of the scalar doubly charmed and doubly bottom tetraquark states using the QCD sum rules.

With the discovery of asymptotic freedom in 1973 Quantum Chromodynamics (QCS) was born. It was soon realized that the study of nonperturbative effects would be crucial in order to understand color confinement, chiral symmetry breaking and, of course, to achieve a quantitative understanding of bound states and low energy dynamics. It was also realized, ...

Using the potential model and thermodynamical quantities obtained in lattice gauge calculations, we determine the spontaneous dissociation temperatures of color-singlet quarkonia and the 'quark drip lines' which separate the region of bound quarkonium states from the unbound region. The dissociation temperatures of J/{psi} and {chi}b in ...

We discuss recent lattice results on in-medium properties of hadrons and focus on thermal properties of heavy quark bound states. We will clarify the relation between heavy quark free energies and potentials used to analyse the melting of heavy quark bound states. Furthermore, we present calculations of meson ...

Heavy quarkonium is perhaps the best QCD laboratory in existence. Much of what we presently know about the fundamental interactions in nature has resulted from the study of two-body bound states. The hydrogen atom, the deuteron and positronium have provided valuable mechanisms for studying quantum mechanics, the theory of nuclear ...

We apply the variational method with a large basis of interpolating operators to demonstrate the feasibility of extracting multiple excited states in char- monium from lattice QCD. The calculation is performed in the quenched approximation to QCD, using t...

Collider experiments have recently measured the production cross section of hard jets separated by a rapidity gap as a function of transverse momentum and gap size. We show that these measurements reveal the relative frequencies for the production of rapidity gaps in quark-quark, quark-gluon and gluon-gluon interactions. The results are at variance with the idea that the exchange of 2 gluons ...

The combination of Anti-de Sitter space (AdS) methods with light-front holography leads to a semi-classical first approximation to the spectrum and wavefunctions of meson and baryon light-quark bound states. Starting from the bound-state Hamiltonian equation of motion in QCD, we derive relativistic light-front wave ...

We present results for the binding energies for {sup 4}He and {sup 3}He nuclei calculated in quenched lattice QCD at the lattice spacing of a=0.128 fm with a heavy quark mass corresponding to m{sub {pi}=}0.8 GeV. Enormous computational cost for the nucleus correlation functions is reduced by avoiding redundancy of equivalent contractions stemming from permutation symmetry of ...

In this paper, we study generic nonlocal Nambu-Jona-Lasinio models for four-dimensional QCD in the limit of a large number of colors. We diagonalize, through a Bogoliubov-type transformation, the Hamiltonian of the model completely in terms of the compound operators creating/annihilating mesons--bound states of dressed quarks and ...

We show how expansions in powers of Planck�s constant ?=h/2? can give new insights into perturbative and nonperturbative properties of quantum field theories. Since ? is a fundamental parameter, exact Lorentz invariance and gauge invariance are maintained at each order of the expansion. The physics of the ? expansion depends on the scheme; i.e., different expansions are obtained depending on ...

We study the evolution of heavy quarkonium states with temperature in a Quark Gluon Plasma (QGP) in terms of the in-medium QQ T-matrix obtained from a reduced Bethe-Salpeter equation. The interaction potential is extracted from finite-temperature lattice QCD calculations of the QQ internal energy. The quarkonium spectral functions and Euclidean correlators ...

The bound state of a quark and an anti quark, quarkonium, is discussed as a means to investigate the nature of the strong force. An analogy is made between positronium and quarkonium and quantum electrodynamics which describes positronium and quantum chromodynamics which describes quarkonium. There is a review of basic concepts applicable to both systems ...

Recent lattice QCD calculations have reported evidence for the existence of a bound state with strangeness -2 and baryon number 2 at quark masses somewhat higher than the physical values. By developing a description of the dependence of this binding energy on the up, down and strange quark masses that allows a controlled chiral ...

Recent lattice QCD calculations have reported evidence for the existence of a bound state with strangeness -2 and baryon number 2 at quark masses somewhat higher than the physical values. By developing a description of the dependence of this binding energy on the up, down and strange quark masses that allows a controlled chiral ...

Electroweak symmetry breaking may be naturally induced by the observed quark and gauge fields in extra dimensions without a fundamental Higgs field. The authors show that a composite Higgs doublet can arise as a bound state of (t,b){sub L} and a linear combination of the Kaluza-Klein states of t{sub R}, due to QCD ...

We investigate the H-dibaryon, an I(JP)=0(0+) with s=-2, in the chiral and continuum regimes on anisotropic lattices in quenched QCD. Simulations are performed on modest lattices with refined techniques to obtain results with high accuracy over a spatial lattice spacing in the range of as�0.19�0.40fm. We present results for the energy difference between the ground ...

We consider a confining Yang-Mills theory without goldstone bosons which could describe the bosonic sector of the weak interactions. This model can be gauge invariantly regularized on a lattice. Our strong coupling analysis of the low-lying bound state spectrum indicates that the vector isotriplet bound state (the ...

J/? and ?c above the QCD critical temperature Tc are studied in anisotropic quenched lattice QCD, considering whether the cc� systems above Tc are spatially compact (quasi-)bound states or scattering states. We adopt the standard Wilson gauge action and O(a)-improved Wilson quark action with ...

The heavy fourth generation of quarks that have sufficiently small mixing with the three known standard model families form hadrons. In the present work, we calculate the masses and decay constants of mesons containing either both quarks from the fourth generation or one from the fourth family and the other from known third family standard model quarks in the framework of the ...

We show how the string amplitude {phi}(z) defined on the fifth dimension in AdS{sub 5} space can be precisely mapped to the light-front wave functions of hadrons in physical space-time. We find an exact correspondence between the holographic variable z and an impact variable {zeta}, which represents the measure of transverse separation of the constituents within the hadrons. In addition, we derive ...

The bosonized QCD2+QED2 system for quarks with two flavors contains QCD2 and QED2 bound states, with an isoscalar photon at about 25 MeV and an isovector (I = 1,I3 = 0) photon at about 44 MeV. Consequently, when a quark and an antiquark at the two ends of a string pulls apart from each other at high energies, ...

The bosonized QCD2+QED2 system for quarks with two flavors contains QCD2 and QED2 bound states, with an isoscalar photon at about 25 MeV and an isovector (I=1 J_{3}=0) photon at about 44 MeV. Consequently, when a quark and antiquark at the two ends of a string pulls apart from each other at high energies, hadrons ...

We examine the stability of hadron resonance gas models by extending them to include undiscovered resonances through the Hagedorn formula. We find that the influence of unknown resonances on thermodynamics is large but bounded. We model the decays of resonances and investigate the ratios of particle yields in heavy-ion collisions. We find that observables such as hydrodynamics ...

This paper provides an overview of the possible role of Quantum Chromo Dynamics (QDC) for neutron stars and strange stars. The fundamental degrees of freedom of QCD are quarks, which may exist as unconfined (color superconducting) particles in the cores of neutron stars. There is also the theoretical possibility that a significantly large number of up, down, and strange quarks ...

If the lighter top squark has no kinematically allowed two-body decays that conserve flavor, then it will live long enough to form hadronic bound states. The observation of the diphoton decays of stoponium could then provide a uniquely precise measurement of the top squark mass. In this paper, we calculate the cross section for the production of stoponium ...

We show how the string amplitude phi(z) defined on the fifth dimension in AdS5 space can be precisely mapped to the light-front wave functions of hadrons in physical space-time. We find an exact correspondence between the holographic variable z and an impact variable zeta, which represents the measure of transverse separation of the constituents within the hadrons. In addition, we derive effective ...

We show how the string amplitude {Phi}(z) defined on the fifth dimension in AdS{sub 5} space can be precisely mapped to the light-front wavefunctions of hadrons in physical spacetime. We find an exact correspondence between the holographic variable z and an impact variable {zeta}, which represents the measure of transverse separation of the constituents within the hadrons. In addition, we derive ...

The scalar productions in heavy meson decays can provide a good platform to study not only heavy flavor physics but also their own physical properties in a dramatically different way. In this work, based on the assumption of two-quark structure of the scalars, the charmless hadronic Bc?SP,SV decays (here, S, P, and V denote the light scalar, pseudoscalar, and vector mesons, respectively) are ...

Comparing the result of inserting a complete set of physical states in a time ordered product of b decay currents with the operator product expansion gives a class of zero recoil sum rules. They sum over physical states with excitation energies less than ?, where ? is much greater than the QCD scale and much less than the heavy charm ...

The theory of the strong interaction, Quantum Chromodynamics (QCD), describes the generation of hadronic masses and the state of hadronic matter during the early stages of the evolution of the universe. As a complement, experiments with ultracold fermionic atoms provide a clean environment to benchmark our understanding of dynamical formation of ...

We study the temperature dependence of the pseudoscalar meson properties in a relativistic bound-state approach exhibiting the chiral behavior mandated by QCD. Concretely, we adopt the Dyson-Schwinger approach with a rank-2 separable model interaction. After extending the model to the strange sector and fixing its parameters at zero temperature, T=0, we ...

We calculate the lowest-order charm and beauty parton distribution functions in and fragmentation functions into D and B mesons using the operator definitions of factorized perturbative quantum chromodynamics (QCD). In the vacuum, we find the leading corrections that arise from the structure of the final-state hadrons. Quark-antiquark potentials extracted ...

We calculate the lowest-order charm and beauty parton distribution functions in and fragmentation functions into D and B mesons using the operator definitions of factorized perturbative quantum chromodynamics (QCD). In the vacuum, we find the leading corrections that arise from the structure of the final-state hadrons. Quark-antiquark potentials extracted ...

Many anomalies suggest that the proton itself is a much more complex object than suggested by simple non-relativistic quark models. Recent analyses of the proton distribution amplitude using QCD sum rules points to highly-nontrivial proton structure. Solutions to QCD in one-space and one-time dimension suggest that the momentum distributions of non-valence ...

The authors review the light-cone Fock state representation and its associated light-cone factorization scheme as a method for encoding the flavor, momentum, and helicity properties of hadrons in the form of universal process-independent and frame-independent amplitudes. Discrete light-cone quantization (DLCQ) provides a matrix representation of the QCD ...

Ongoing calculations on the QCDOC supercomputer at Brookhaven National Laboratory and the APEnext installation at the University of Bielefeld aim to determine the critical temperature of the QCD phase transition as well as the equation of state with almos...

The decays of excited baryons are analyzed using the 1/Nc expansion of QCD. These studies are performed up to order 1/Nc, and include positive and negative parity states.

The decays of excited baryons are analyzed using the 1/Nc expansion of QCD. These studies are performed up to order 1/Nc, and include positive and negative parity states.

In QCD with massive quarks it is shown that the selfconsistency condition of the scattering theory in the asymptotic dynamics representation leads to the statement that there are no free quarks in asymptotic states on the level of perturbation theory. (At...

We summarize the state of the art of resummation techniques in the small-x limit of perturbative QCD.

Four-quark states with different internal clusters are discussed within the constituent quark model. It is pointed out that the diquark concept is not meaningful in the construction of a tetraquark interpolating current in the QCD sum-rule approach, and hence existing sum-rule studies of four-quark states are incomplete. An updated ...

We perform a QCD sum rule analysis for the f{sub 0} light tetraquark taking into account the contribution arising from the two pion intermediate state. With the interpolating currents of the different chiral combinations of scalar and pseudoscalar diquarks, it is demonstrated that the interpolating current with maximum chirality has a large coupling to the ...

Recent results on QCD tests at the Z{sup o} resonance are described. Measurements of Color factor ratios, and studies of final state photon radiation are performed by the LEP experiments. QCD tests using a longitudinally polarized beam are reported by the SLD experiment.

The authors report on this progress in the calculation of nuclear ground-state properties using effective Lagrangians whose construction is constrained by QCD scales and chiral symmetry. Good evidence is found that QCD and chiral symmetry apply to finite nuclei.

It is shown that a quantum state consisting of a condensate of color magnetic flux tubes is formed in QCD for a rather weak coupling g exp 2 /4 pi =0.37. This result is obtained in a systematic search for energy minimalizing forms of the QCD unstable magn...

Quantum chromodynamics (QCD) is the theory of the strong interaction, explaining (for example) the binding of three almost massless quarks into a much heavier proton or neutron--and thus most of the mass of the visible Universe. The standard model of particle physics predicts a QCD-related transition that is relevant for the evolution of the early ...

Theoretical and phenomenological evidence is now accumulating that the QCD coupling becomes constant at small virtuality; i.e., {alpha}{sub s}(Q{sup 2}) develops an infrared fixed point in contradiction to the usual assumption of singular growth in the infrared. For example, the hadronic decays of the {tau} lepton can be used to determine the effective charge {alpha}{sub ...

The general structure of QCD meshes remarkably well with the facts of the hadronic world, especially quark-based spectroscopy, current algebra, the approximate point-like structure of large momentum transfer inclusive reactions, and the logarithmic violation of scale invariance in deep inelastic lepton-hadron reactions. QCD has been successful in ...

We consider the existence of bound states of two mesons in an imaginary-time formulation of lattice QCD. We analyze an SU(3) theory with two flavors in 2+1 dimensions and two-dimensional spin matrices. For a small hopping parameter and a sufficiently large glueball mass, as a preliminary, we show the existence of isoscalar and ...

Due to the kinematic and dynamic simplifications possible because of the large mass of heavy quark bound states, certain properties of these systems can be quantitatively analyzed within the framework of quantum chromodynamics. It is clear that dimensionally the size of the bound state is proportional to the ...

The discussion covers quarks as we know them, the classification of ordinary mesons in terms of constituent quarks, hidden charm states and charmed mesons, bottom quarks, positronium as a model for quarti q, quantum chromodynamics and its foundation in experiment, the charmonium model, the mass of states, fine structure and hyperfine structure, ...

The lecture is divided in two parts. The first one deals with an introduction to the physics of hot, dense many-particle systems in quantum field theory [1, 2]. The basics of the path integral approach to the partition function are explained for the example of chiral quark models. The QCD phase diagram is discussed in the meanfield approximation while QCD ...

We present different aspects of the theoretical study of matter under extreme conditions, ranging from the interpretation of experimental signatures, with some consequences in nuclear structure, to the prediction of hadron parameters at finite temperature. We begin with a study of binding energies of charmonium bound states in the environment created by a ...

We find a correspondence between semiclassical QCD quantized on the light-front and a dual gravity model in anti--de Sitter (AdS) space, thus providing an initial approximation to QCD in its strongly coupled regime. This correspondence--light-front holography--leads to a light-front Hamiltonian and relativistic bound-state wave ...

We find a correspondence between semiclassical QCD quantized on the light-front and a dual gravity model in anti-de Sitter (AdS) space, thus providing an initial approximation to QCD in its strongly coupled regime. This correspondence - light-front holography - leads to a light-front Hamiltonian and relativistic bound-state wave ...

Light-cone quantization of gauge theories is discussed from two perspectives: as a calculational tool for representing hadrons as QCD bound-states of relativistic quarks and gluons, and as a novel method for simulating quantum field theory on a computer. A general non-perturbative method for numerically solving quantum field theories, 'discretized ...

We study the vector meson electro-production off the proton in a QCD inspired model. A calculation of the differential cross section is performed for the J/?,phi meson off the proton. The theoretical results are consistent with the experimental data, and remind us to consider the contribution from the tensor glueball and Odderon to the differential cross section. Since gluons ...

A thermodynamic T-matrix approach for elastic two-body interactions is employed to calculate spectral functions of open and hidden heavy-quark systems in the quark-gluon plasma. This enables the evaluation of quarkonium bound-state properties and heavy-quark diffusion on a common basis and thus to obtain mutual constraints. The two-body interaction kernel is approximated ...

In this thesis, three diffrent topics in high energy particle physics are investigated each of which is a case of theoretical and phenomenological application of perturbative Quantum Chromodynamics. The first topic is addressed to the structure of nucleons as probed in deep-inelastic lepton-nucleon scattering. Since, at present, meaningful calculations in Quantum Chromodynamics ...

The main thrust of this talk is to review and discuss various topics in both perturbative and non-perturbative QCD that are, by and large, model independent. This inevitably means that we shall rely heavily on the renormalization group and asymptotic freedom. Although this usually means that one has to concentrate on high energy phenomena, there are some physical processes ...

In a preceding study in the heavy quark limit of QCD, it has been demonstrated that the best lower bound on the curvature of the Isgur-Wise function {xi}(w) is {xi}{sup ''}(1)>(1/5)[4{rho}{sup 2}+3({rho}{sup 2}){sup 2}]>(15/16). The quadratic term ({rho}{sup 2}){sup 2} is dominant in a nonrelativistic expansion in the light ...

We calculate the ratios R1 = ?(?c --> ??)/?(D+ --> ?+??) and R2 = ?(? --> e+e-)/?(J/? --> e+e-) in a bound state quark model with QCD Bethe-Salpeter wave functions for these mesons. The result shows that R1 and R2 are very sensitive to the constituent quark mass ratios Md/Mc and Mb/Mc respectively, and agree well with the ...

In these lectures the author introduces and explores a range of topics of contemporary interest in hadronic physics: from what drives the formation of a nonzero quark condensate to the effect that mechanism has on light and heavy meson form factors and the properties of the quark-gluon plasma. The trail leads naturally through a discussion of confinement, dynamical chiral symmetry breaking and ...

Analyzing correlation functions of charmonia at finite temperature (T) on 323�(32-96) anisotropic lattices by the maximum entropy method (MEM), we find that J/? and ?c survive as distinct resonances in the plasma even up to T?1.6Tc and that they eventually dissociate between 1.6Tc and 1.9Tc (Tc is the critical temperature of deconfinement). This suggests that the deconfined plasma is ...

We calculate the polarization operator of a valence gluon, which propagates in the confining background in the form of a color-octet bound state. The result leads to the infrared freezing (i.e. finiteness) of the running strong coupling in the vacuum, as well as in the quark-gluon plasma up to the temperature of dimensional reduction. The momentum scale ...

We consider the heavy quark limit of Coulomb gauge QCD, with the truncation of the Yang-Mills sector to include only (dressed) two-point functions. We find that the rainbow-ladder approximation to the gap and Bethe-Salpeter equations is nonperturbatively exact and moreover, we provide a direct connection between the temporal gluon propagator and the quark confinement ...

The structure of the Hamiltonian related to a regularized non-Abelian gauge field theory is discussed in the light of different choices for gauge-invariant wave functionals (loop space, Coulomb, axial, Schwinger gauge). Arguments are given for the suggestion that the Schwinger gauge offers a specially suited framework for the computation of bound-state (hadron) properties. The ...

The null search for the Higgs boson at the Tevatron implies strong constraints on heavy colored particles that increase the gluon-fusion induced production rate of the Higgs. We investigate the implications of the Tevatron exclusion limit on example extensions of the standard model that contain a new scalar state transforming as either an adjoint or a fundamental under the ...

We explain a method for computing the bulk viscosity of strongly coupled thermal plasmas dual to supergravity backgrounds supported by one scalar field. Whereas earlier investigations required the computation of the leading dissipative term in the dispersion relation for sound waves, our method requires only the leading frequency dependence of an appropriate Green's function in the low-frequency ...

The BRST quartet mechanism in infrared Landau gauge QCD is investigated. Based on the observed positivity violation for transverse gluons A the field content of the non-perturbative BRST quartet generated by A is derived. To identify the gluon's BRST-daughter state as well as the Faddeev�Popov-charge conjugated second parent state, a ...

The antiproton storage ring HESR to be constructed at GSI will open up a new range of perturbative and nonperturbative tests of QCD in exclusive and inclusive reactions. I discuss 21 tests of QCD using antiproton beams which can illuminate novel features of QCD. The proposed experiments include the formation of exotic hadrons, ...

The Centerline of Worcester County roads with the address ranges. The centerlines within the bounds of Ocean City, MD were not QC'd by the Worcester Co. ... ...

Exclusive processes provide a window into the bound state structure of hadrons in QCD as well as the fundamental processes which control hadron dynamics at the amplitude level. The natural calculus for describing bound state structure of relativistic composite systems needed for describing ...

An upper bound for the number of bound states of a short range and spherically symmetric potential is given.

Basis invariant characterizations of bound states and bound fraction of a partially ionized hydrogen

We give an overview of the light front holographic approach to strongly coupled QCD, whereby a confining gauge theory quantized on the light front is mapped to a higher-dimensional anti de Sitter (AdS) space incorporating the AdS/CFT correspondence as a useful guide. One can start from the Hamiltonian equation of motion in physical space time by studying the off-shell dynamics ...

The combination of Anti-de Sitter space (AdS) methods with light-front (LF) holography provides a remarkably accurate first approximation for the spectra and wavefunctions of meson and baryon light-quark bound states. The resulting bound-state Hamiltonian equation of motion in QCD leads to relativistic light-front ...

Research in the Maryland Nuclear Theory Group focusses on problems in four basic areas of current relevance. The section on Hadrons in Nuclei reports research into the ways in which the properties of nucleons and the mesons which play a role in the nuclear force are modified in the nuclear medium. QCD sum rules supply a new insight into the decrease of the nucleon`s mass in ...

We calculate near zero recoil the order {alpha}{sub s} corrections to the Bjorken and Voloshin sum rules that bound the B{r_arrow}D{sup ({asterisk})}scr(l){bar {nu}} form factors. These bounds are derived by relating the result of inserting a complete set of physical states in a time-ordered product of weak currents to the operator ...

Heavy colored scalar particles, which exist in many models of new physics, can be pair produced at the LHC via gluon-gluon fusion and possibly form quarkoniumlike bound states. If the scalars are also charged under the electroweak gauge group, these bound states can then decay into electroweak bosons. This yields a ...

Heavy colored scalar particles, which exist in many models of new physics, can be pair produced at the LHC via gluon-gluon fusion and possibly form quarkoniumlike bound states. If the scalars are also charged under the electroweak gauge group, these bound states can then decay into electroweak bosons. This yields a ...

Low energy charmonium-nucleon interaction is of particular interest in this talk. A heavy quarkonium state like the charmonium does not share the same quark flavor with the nucleon so that cc-nucleon interaction might be described by the gluonic van der Waals interaction, which is weak but attractive. Therefore, the information of the strength of cc-nucleon interaction is ...

We consider an imaginary time functional integral formulation of a two-flavor, 3+1 lattice QCD model with Wilson's action and in the strong coupling regime (with a small hopping parameter, ? > 0, and a much smaller plaquette coupling, ? =1/g02>0, so that the quarks and glueballs are heavy). The model has local SU(3)c gauge and global SU(2)f flavor symmetries, and ...

In this paper, we study the 0+ nonet mesons as tetraquark states with interpolating currents inspired by the color-magnetic wave function. This wave function is the eigenfunction of an effective color-magnetic Hamiltonian with the lowest eigenvalue, meaning that the state depicted by this wave function is the most stable one and is the most probable to be ...

The Quark-Gluon-Plasma (QGP) is a highly excited, strongly interacting, hot and dense state of matter. Its degrees of freedom are quarks and gluons which are the basic constituents of quantum chromodynamics (QCD), one of the four fundamental forces of nature. It is believed that shortly after the creation of the universe in the Big Bang all matter was in ...

We present a quenched lattice QCD calculation of spin-1/2 five-quark states with uudds quark content for both positive and negative parities. We do not observe any bound pentaquark state in these channels for either I=0 or I=1. The states we found are consistent with KN scattering ...

The light-front quantization of gauge theories in light-cone gauge provides a frame-independent wavefunction representation of relativistic bound states, simple forms for current matrix elements, explicit unitarity, and a trivial vacuum. In this talk I review the theoretical methods and constraints which can be used to determine these central elements of ...

The light-front quantization of gauge theories in light-cone gauge provides a frame-independent wavefunction representation of relativistic bound states, simple forms for current matrix elements, explicit unitarity, and a trivial vacuum. In this talk I review the theoretical methods and constraints which can be used to determine these central elements of ...

The Dyson-Schwinger equations (DSEs) are a tower of coupled integral equations that relate the Green functions of QCD to one another. Solving these equations provides the solution of QCD. This tower of equations includes the equation for the quark self-energy, which is the analogue of the gap equation in superconductivity, and the Bethe-Salpeter equation, ...

Within the Euclidean effective action approach we propose criteria for the ground state of QCD. Despite a nonvanishing field strength the ground state should be invariant with respect to modified Poincare transformations consisting of a combination of tra...

We calculate the masses of the resonances D_{s0}^{ast}(2317) and D_{s1}(2460) as well as their bottom partners as bound states of a kaon and a D^{(ast)} - and B^{(ast)} -meson, respectively, in unitarized chiral perturbation theory at next-to-leading order. After fixing the parameters in the D_{s0}^{ast}(2317) channel, the calculated mass for the ...

We point out that an unorthodox way to describe the production of rapidity gaps in deep inelastic scattering, recently proposed by Buchmuller and Hebecker, suggests a description of the production of heavy quark bound states which is in agreement with data. The approach questions the conventional treatment of the color quantum number in perturbative ...

We present a short general overview of the main features of exotic models of neutron stars, focusing on the structural and dynamical predictions derived from them. In particular, we discuss the presence of �normal� quark matter and Color-Flavor Locked (CFL) states, including their possible self-bound versions, and mention some different proposals ...

The Lorentz nature of the effective interquark interaction in a heavy-light quarkonium is studied using the vacuum correlators method and the generalized Nambu-Jona-Lasinio potential quark model. An effective scalar interaction is demonstrated to appear self-consistently owing to chiral-symmetry breaking and to dominate for low-lying states in the ...

Mesons are the simplest quark bound system, being made by a quark and an anti-quark pair. Studying their structure and properties is a fundamental step to reach a deep understanding of QCD. For this purpose both a precise determination of the meson spectrum for conventional states and the search for states beyond ...

The ion-ion center of mass energies at the LHC will exceed that at RHIC by nearly a factor of 30, providing exciting opportunities for addressing unique physics issues in a completely new energy domain. Some highlights of this new physics domain are presented here. We briefly describe how these collisions will provide new insights into the high density, low momentum gluon content of the nucleus ...