Form Factors and Dyson-Schwinger Equations (2008)
A synopsis exemplifying the employment of Dyson-Schwinger equations in the calculation and explanation of hadron electromagnetic form factors and related phenomena. In particular the contribution:...
On unifying the description of meson and baryon properties (2008)
Eichmann, G., Cloet, I. C., Alkofer, R., Krassnigg, A., Roberts, C. D.
A Poincare' covariant Faddeev equation is presented, which enables the simultaneous prediction of meson and baryon observables using the leading-order in a truncation of the Dyson-Schwinger equations...
Regarding confinement and dynamical chiral symmetry breaking in QED3 (2008)
Bashir, A., Raya, A., Cloet, I. C., Roberts, C. D.
We establish that QED3 can possess a critical number of flavours, N_f^c, associated with dynamical chiral symmetry breaking if, and only if, the fermion wave function renormalisation and photon...
Current quark mass dependence of nucleon magnetic moments and radii (2008)
Cloet, I. C., Eichmann, G., Flambaum, V. V., Roberts, C. D., Bhagwat, M. S., Holl, A.
A calculation of the current-quark-mass-dependence of nucleon static electromagnetic properties is necessary in order to use observational data as a means to place constraints on the variation of...
Perspective on rainbow-ladder truncation (2008)
Eichmann, G., Alkofer, R., Cloet, I. C., Krassnigg, A., Roberts, C. D.
Prima facie the systematic implementation of corrections to the rainbow-ladder truncation of QCD's Dyson-Schwinger equations will uniformly reduce in magnitude those calculated mass-dimensioned...
Aspects of Hadron Physics (2008)
Roberts, C. D., Bhagwat, M. S., Wright, S. V., Holl, A.
Detailed investigations of the structure of hadrons are essential for understanding how matter is constructed from the quarks and gluons of Quantum chromodynamics (QCD), and amongst the questions...
Hadron Properties and Dyson-Schwinger Equations (2007)
An overview of the theory and phenomenology of hadrons and QCD is provided from a Dyson-Schwinger equation viewpoint. Following a discussion of the definition and realisation of light-quark...
Dynamics, Symmetries and Hadron Properties (2007)
Cloet, I. C., Krassnigg, A., Roberts, C. D.
We provide a snapshot of Dyson-Schwinger equation applications to the theory and phenomenology of hadrons. Exact results for pseudoscalar mesons are highlighted, with details relating to the U_A(1)...
Covariance, Dynamics and Symmetries, and Hadron Form Factors (2007)
Bhagwat, M. S., Cloet, I. C., Roberts, C. D.
We summarise applications of Dyson-Schwinger equations to the theory and phenomenology of hadrons. Some exact results for pseudoscalar mesons are highlighted with details relating to the U_A(1)...
Schwinger functions and light-quark bound states (2007)
Bhagwat, M. S., Hoell, A., Krassnigg, A., Roberts, C. D., Wright, S. V.
We examine the applicability and viability of methods to obtain knowledge about bound-states from information provided solely in Euclidean space. Rudimentary methods can be adequate if one only...
Chiral Dynamics from Dyson-Schwinger Equations (2006)
Bhagwat, M. S., Roberts, C. D.
A strongly momentum-dependent dressed-quark mass function is basic to QCD. It is central to the appearance of a constituent-quark mass-scale and an existential prerequisite for Goldstone modes....
Bhagwat, M. S., Krassnigg, A., Maris, P., Roberts, C. D.
In this summary of the application of Dyson-Schwinger equations to the theory and phenomenology of hadrons, some deductions following from a nonperturbative, symmetry-preserving truncation are...
Nucleon electromagnetic form factors (2006)
Arrington, J., Roberts, C. D., Zanotti, J. M.
Elastic electromagnetic nucleon form factors have long provided vital information about the structure and composition of these most basic elements of nuclear physics. The form factors are a...
Theory and Phenomenology of Hadrons (2006)
Bhagwat, M. S., Holl, A., Krassnigg, A., Roberts, C. D.
This Dyson-Schwinger equation (DSE) aperc,u highlights recent applications to mesons. It reports features of, and results for, pseudoscalar and scalar bound-state residues in vacuum polarisations,...
Meson spectroscopy and properties using Dyson-Schwinger equations (2006)
Krassnigg, A., Roberts, C. D., Wright, S. V.
We study pseudoscalar and scalar mesons using a practical and symmetry preserving truncation of QCD's Dyson-Schwinger equations. We investigate and compare properties of ground and radially excited...
Hadron Physics and Dyson-Schwinger Equations (2006)
Hoell, A., Roberts, C. D., Wright, S. V.
Detailed investigations of the structure of hadrons are essential for understanding how matter is constructed from the quarks and gluons of QCD, and amongst the questions posed to modern hadron...
Schwinger functions and light-quark bound states, and sigma terms (2005)
Hoell, A., Maris, P., Roberts, C. D., Wright, S. V.
We explore the viability of using solely spacelike information about a Schwinger function to extract properties of bound states. In a concrete example it is not possible to determine properties of...
Pair production and optical lasers (2005)
Blaschke, D. B., Prozorkevich, A. V., Roberts, C. D., Schmidt, S. M., Smolyansky, S. A.
Electron-positron pair creation in a standing wave is explored using a parameter-free quantum kinetic equation. Field strengths and frequencies corresponding to modern optical lasers induce a...
Sigma Terms of Light-Quark Hadrons (2005)
Flambaum, V. V., Hoell, A., Jaikumar, P., Roberts, C. D., Wright, S. V.
A calculation of the current-quark mass dependence of hadron masses can help in using observational data to place constraints on the variation of nature's fundamental parameters. A hadron's...
Electromagnetic properties of ground and excited state pseudoscalar mesons (2005)
Hoell, A., Krassnigg, A., Maris, P., Roberts, C. D., Wright, S. V.
The axial-vector Ward-Takahashi identity places constraints on particular properties of every pseudoscalar meson. For example, in the chiral limit all pseudoscalar mesons, except the Goldstone mode,...
On Nucleon Electromagnetic Form Factors: A Pre'cis (2005)
Hoell, A, Alkofer, R., Kloker, M., Krassnigg, A., Roberts, C. D., Wright, S. V.
Electron scattering at large Q^2 probes a nucleon's quark core. This core's contribution to electromagnetic form factors may be calculated using Poincare' covariant Faddeev amplitudes combined with a...
On Nucleon Electromagnetic Form Factors (2004)
Alkofer, R., Hoell, A., Kloker, M., Krassnigg, A., Roberts, C. D.
A Poincare' covariant Faddeev equation, which describes baryons as composites of confined-quarks and -nonpointlike-diquarks, is solved to obtain masses and Faddeev amplitudes for the nucleon and...
On the complexion of pseudoscalar mesons (2004)
Hoell, A., Krassnigg, A., Roberts, C. D., Wright, S. V.
A strongly momentum-dependent dressed-quark mass function is basic to QCD. It is central to the appearance of a constituent-quark mass-scale and an existential prerequisite for Goldstone modes....
Confinement, DCSB, Bound States, and the Quark-Gluon Vertex (2004)
Holl, A., Krassnigg, A., Roberts, C. D.
Aspects of the dressed-quark-gluon vertex and their role in the gap and Bethe-Salpeter equations are briefly surveyed using an intuitive model. The model allows one to elucidate why a linear...
Pseudoscalar Meson Radial Excitations (2004)
Hoell, A., Krassnigg, A., Roberts, C. D.
Goldstone modes are the only pseudoscalar mesons to possess a nonzero leptonic decay constant in the chiral limit when chiral symmetry is dynamically broken. The decay constants of their radial...
Aspects and consequences of a dressed-quark-gluon vertex (2004)
Bhagwat, M. S., Hoell, A., Krassnigg, A., Roberts, C. D., Tandy, P. C.
Features of the dressed-quark-gluon vertex and their role in the gap and Bethe-Salpeter equations are explored. It is argued that quenched lattice data indicate the existence of net attraction in the...
DSEs and pseudoscalar mesons: an aperc,u (2003)
Hoell, A., Krassnigg, A., Roberts, C. D.
An hallmark of present-day Dyson-Schwinger equation applications in hadron physics is the existence of a systematic and symmetry preserving truncation scheme. This enables the proof of exact results;...
Dyson-Schwinger Equations: An Instrument for Hadron Physics (2003)
Dyson-Schwinger equations furnish a Poincare' covariant approach to hadron physics. They reveal that dynamical chiral symmetry breaking is tied to the long-range behaviour of the strong interaction...
DSEs, the pion, and related matters (2003)
We recapitulate on aspects of Dyson-Schwinger equation studies relevant to pseudoscalar mesons: lattice confirmation of the DSE prediction that propagators are nonperturbatively dressed in the...
Regarding proton form factors (2003)
Bloch, J. C. R., Krassnigg, A., Roberts, C. D.
The proton's elastic electromagnetic form factors are calculated using an Ansatz for the nucleon's Poincare' covariant Faddeev amplitude that only retains scalar diquark correlations. A spectator...
Unifying aspects of light- and heavy-systems (2003)
Dyson-Schwinger equations furnish a Poincare' covariant framework within which to study hadrons. A particular feature is the existence of a nonperturbative, symmetry preserving truncation that...
Analysis of a quenched lattice-QCD dressed-quark propagator (2003)
Bhagwat, M. S., Pichowsky, M. A., Roberts, C. D., Tandy, P. C.
Quenched lattice-QCD data on the dressed-quark Schwinger function can be correlated with dressed-gluon data via a rainbow gap equation so long as that equation's kernel possesses enhancement at...
Aspects of Dynamical Chiral Symmetry Breaking (2003)
Dynamical chiral symmetry breaking is a nonperturbative phenomenon that may be studied using QCD's gap equation. Model-independent results can be obtained with a nonperturbative and symmetry...
Dyson-Schwinger equations: a tool for hadron physics (2003)
Dyson-Schwinger equations furnish a Poincare' covariant framework within which to study hadrons. A particular feature is the existence of a nonperturbative, symmetry preserving truncation that...
Concerning the quark condensate (2003)
Langfeld, K., Pullirsch, R., Markum, H., Roberts, C. D., Schmidt, S. M.
A continuum expression for the trace of the massive dressed-quark propagator is used to explicate a connection between the infrared limit of the QCD Dirac operator's spectrum and the quark condensate...
Facets of confinement and dynamical chiral symmetry breaking (2002)
Maris, P., Raya, A., Roberts, C. D., Schmidt, S. M.
The gap equation is a cornerstone in understanding dynamical chiral symmetry breaking and may also provide clues to confinement. A symmetry-preserving truncation of its kernel enables proofs of...
Quantum effects with an X-ray free electron laser (2002)
Roberts, C. D., Schmidt, S. M., Vinnik, D. V.
A quantum kinetic equation coupled with Maxwell's equation is used to estimate the laser power required at an XFEL facility to expose intrinsically quantum effects in the process of QED vacuum decay...
Bethe-Salpeter equation and a nonperturbative quark-gluon vertex (2002)
Bender, A., Detmold, W., Roberts, C. D., Thomas, A. W.
A Ward-Takahashi identity preserving Bethe-Salpeter kernel can always be calculated explicitly from a dressed-quark-gluon vertex whose diagrammatic content is enumerable. We illustrate that fact...
Nucleon mass and pion loops (2002)
Hecht, M. B., Oettel, M., Roberts, C. D., Schmidt, S. M., Tandy, P. C., Thomas, A. W.
Poincare' covariant Faddeev equations for the nucleon and Delta are solved to illustrate that an internally consistent description in terms of confined-quark and nonpointlike...
Nucleon mass and pion loops (2002)
Hecht, M. B., Roberts, C. D., Oettel, M., Thomas, A. W., Schmidt, S. M., Tandy, P. C.
Nucleon mass and pion loops (2002)
Hecht, M. B., Roberts, C. D., Oettel, M., Thomas, A. W., Schmidt, S. M., Tandy, P. C.
Goldstone Boson's Valence-Quark Distribution (2001)
Dynamical chiral symmetry breaking (DCSB) is one of the keystones of low-energy hadronic phenomena. Dyson-Schwinger equations provide a model-independent quark-level understanding and correlate that...
Modern Dyson-Schwinger Equation Studies (2001)
The dichotomy of the pion as QCD's Goldstone mode and a bound state of massive constituents is easily understood using the Dyson-Schwinger equations. That provides the foundation for an efficacious...
Pair Creation and an X-ray Free Electron Laser (2001)
Alkofer, R., Hecht, M. B., Roberts, C. D., Schmidt, S. M., Vinnik, D. V.
Using a quantum kinetic equation coupled to Maxwell's equation we study the possibility that focused beams at proposed X-ray free electron laser facilities can generate electric field strengths large...
The Character of Goldstone Bosons (2001)
Hecht, M. B., Roberts, C. D., Schmidt, S. M.
A succinct review of the QCD gap equation and dynamical chiral symmetry breaking; their connection with Bethe-Salpeter equations and resolving the dichotomous nature of the pion; the calculation of...
Plasma production and thermalisation in a strong field (2001)
Vinnik, D. V., Prozorkevich, A. V., Smolyansky, S. A., Toneev, V. D., Hecht, M. B., Roberts, C. D., ...
Aspects of the formation and equilibration of a quark-gluon plasma are explored using a quantum kinetic equation, which involves a non-Markovian, Abelian source term for quark and antiquark...
Neutron electric dipole moment: Constituent-dressing and compositeness (2001)
Hecht, M. B., Roberts, C. D., Schmidt, S. M.
Contributions to the neutron's EDM, are calculated using a well-constrained Ansatz for the nucleon's Poincare' covariant Fadde'ev amplitude. The momentum-dependent quark dressing amplifies the...
Pair creation and plasma oscillations (2000)
Prozorkevich, A. V., Vinnik, D. V., Schmidt, S. M., Hecht, M. B., Roberts, C. D.
We describe aspects of particle creation in strong fields using a quantum kinetic equation with a relaxation-time approximation to the collision term. The strong electric background field is...
Hecht, M. B., Roberts, C. D., Schmidt, S. M.
We describe aspects of the role that diquark correlations play in understanding baryon structure and interactions. The significance of diquarks in that application motivates a study of the...
Dyson-Schwinger Equations - aspects of the pion (2000)
Hecht, M. B., Roberts, C. D., Schmidt, S. M.
The contemporary use of Dyson-Schwinger equations in hadronic physics is exemplified via applications to the calculation of pseudoscalar meson masses, and inclusive deep inelastic scattering with a...
Contemporary applications of Dyson-Schwinger equations (2000)
Hecht, M. B., Roberts, C. D., Schmidt, S. M.
We illustrate the contemporary application of Dyson-Schwinger equations using two examples: the calculation of pseudoscalar meson masses, an associated model-independent mass formula and the approach...
Valence-quark distributions in the pion (2000)
Hecht, M. B., Roberts, C. D., Schmidt, S. M.
We calculate the pion's valence-quark momentum-fraction probability distribution using a Dyson-Schwinger equation model. Valence-quarks with an active mass of 0.30 GeV carry 71% of the pion's...
Heavy-Meson Observables via Dyson-Schwinger Equations (2000)
Ivanov, M. A., Kalinovsky, Yu. L., Roberts, C. D.
We summarise a Dyson-Schwinger-equation-based calculation of an extensive range of light- and heavy-meson observables, characterised by heavy-meson leptonic decays, semileptonic heavy-to-heavy and...
DSE Hadron Phenomenology (2000)
Hecht, M. B., Roberts, C. D., Schmidt, S. M.
A perspective on the contemporary use of Dyson-Schwinger equations, focusing on some recent phenomenological applications: a description and unification of light-meson observables using a...
Dyson-Schwinger Equations: Density, Temperature and Continuum Strong QCD (2000)
Roberts, C. D., Schmidt, S. M.
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...
Temperature, chemical potential and the rho meson (2000)
Roberts, C. D., Schmidt, S. M.
We describe some applications of the Dyson-Schwinger equations at nonzero-(T,mu). Employing a simple model dressed-gluon propagator we determine the boundary of the deconfinement phase transition and...
T-dependence of pseudoscalar and scalar correlations (2000)
Maris, P., Roberts, C. D., Schmidt, S. M., Tandy, P. C.
Inhomogeneous pseudoscalar and scalar Bethe-Salpeter equations solved using a renormalisation-group-improved rainbow-ladder truncation exhibit bound state poles below and above T_c, the critical...
Selected nucleon form factors and a composite scalar diquark (1999)
Bloch, J. C. R., Roberts, C. D., Schmidt, S. M.
A covariant, composite scalar diquark, Fadde'ev amplitude model for the nucleon is used to calculate pseudoscalar, isoscalar- and isovector-vector, axial-vector and scalar nucleon form factors. The...
Memory effects and thermodynamics in strong field plasmas (1999)
Bloch, J. C. R., Roberts, C. D., Schmidt, S. M.
We study the evolution of a strong field plasma using a quantum Vlasov equation with a non-Markovian source term and a simple collision term, and calculate the time dependence of the energy- and...
K -> pi pi and a light scalar meson (1999)
Bloch, J. C. R., Ivanov, M. A., Mizutani, T., Roberts, C. D., Schmidt, S. M.
We explore the Delta-I= 1/2 rule and epsilon'/epsilon in K -> pi pi transitions using a Dyson-Schwinger equation model. Exploiting the feature that QCD penguin operators direct K^0_S transitions...
Nucleon form factors and a nonpointlike diquark (1999)
Bloch, J. C. R., Roberts, C. D., Schmidt, S. M., Bender, A., Frank, M. R.
Nucleon form factors are calculated on q^2 in [0,3] GeV^2 using an Ansatz for the nucleon's Fadde'ev amplitude motivated by quark-diquark solutions of the relativistic Fadde'ev equation. Only the...
Diquarks: condensation without bound states (1999)
Bloch, J. C. R., Roberts, C. D., Schmidt, S. M.
We employ a bispinor gap equation to study superfluidity at nonzero chemical potential: mu .neq. 0, in two- and three-colour QCD. The two-colour theory, QC2D, is an excellent exemplar: the order of...
Pair creation: back-reactions and damping (1999)
Bloch, J. C. R., Mizerny, V. A., Prozorkevich, A. V., Roberts, C. D., Schmidt, S. M., Smolyansky, S. A., ...
We solve the quantum Vlasov equation for fermions and bosons, incorporating spontaneous pair creation in the presence of back-reactions and collisions. Pair creation is initiated by an external...
Describing a1 and b1 decays (1999)
Bloch, J. C. R., Kalinovsky, Yu. L., Roberts, C. D., Schmidt, S. M.
Two-body pion-radiating and weak decays of light axial-vector mesons and the rho are studied as a phenomenological application of the QCD Dyson-Schwinger equations. Models based on the rainbow-ladder...
Heavy Meson Observables (1999)
Ivanov, M. A., Kalinovsky, Yu. L., Roberts, C. D.
An accurate and unified description of the non-hadronic electroweak interactions of light- and heavy-mesons is possible when the dressing of quark propagators and the finite size of hadronic bound...
Nucleon form factors and a nonpointlike diquark (1999)
Bloch, J. C.R., Roberts, C. D., Schmidt, S. M., Bender, A., Frank, M. R.
Nucleon form factors and a nonpointlike diquark (1999)
Bloch, J. C.R., Roberts, C. D., Schmidt, S. M., Bender, A., Frank, M. R.
Survey of heavy-meson observables (1998)
Ivanov, M. A., Kalinovsky, Yu. L., Roberts, C. D.
We employ a Dyson-Schwinger equation model to effect a unified and uniformly accurate description of light- and heavy-meson observables, which we characterise by heavy-meson leptonic decays,...
Design and Fabrication of an Elastomer Test Machine. (1998)
Das-Gupta, D. K., Roberts, C. D.
An Elastomer Test machine has been designed and constructed as a unique test bed for elastomer compounds which are used on road vehicles and caterpillar tracks. The machine simulates complex wearing...
Heavy Meson Observables and Dyson-Schwinger Equations (1998)
Ivanov, M. A., Kalinovsky, Yu. L., Maris, P., Roberts, C. D.
Dyson-Schwinger equation (DSE) studies show that the b-quark mass-function is approximately constant, and that this is true to a lesser extent for the c-quark. These observations provide the basis...
Analysis of chiral and thermal susceptibilities (1998)
Blaschke, D., Hoell, A., Roberts, C. D., Schmidt, S.
We calculate the chiral and thermal susceptibilities for two confining Dyson-Schwinger equation models of QCD with two light flavours, a quantitative analysis of which yields the critical exponents,...
A Dynamical, Confining Model and Hot Quark Stars (1998)
D. Blaschke, H. Grigorian, G. Poghosyan, C. D. Roberts
We study the structure and stability of nonstrange quark stars at finite temperature using an equation of state (EOS) obtained in a simple, confining Dyson-Schwinger equation model of QCD, and...
Chemical potential dependence of pi and rho properties (1998)
Maris, P., Roberts, C. D., Schmidt, S.
Using a confining, Dyson-Schwinger equation model of QCD at finite temperature (T) and chemical potential (mu) we study the behaviour of , m_pi, f_pi and the masses of the rho- and phi-mesons. For...
A dynamical, confining model and hot quark stars (1998)
Blaschke, D., Grigorian, H., Poghosyan, G., Roberts, C. D., Schmidt, S.
We explore the consequences of an equation of state (EOS) obtained in a confining Dyson-Schwinger equation model of QCD for the structure and stability of nonstrange quark stars at finite-T, and...