Dyson-Schwinger equations and hadronic observables in QCD
- Argonne National Lab., IL (United States)
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 covariant Fadde`ev equation, whose solution provides baryon bound state amplitudes. Solving the tower of DSEs provides the solution of QCD; a field theory being completely defined when all of its n-point functions are known. The nonperturbative DSE approach is being developed as a complement and computationally less-intensive alternative to numerical simulations of lattice-QCD. Significant progress has recently been made and it is now possible to make direct comparisons between quantities calculated using the DSE approach and the results of numerical simulations of Abelian gauge theories. Cross-fertilization between numerical simulations of lattice-QCD and DSE studies is a presently underutilized but particularly useful means of developing a detailed understanding of nonperturbative QCD. In this presentation the author describes how symmetries are used to ensure that the sensitivity of calculated observables to the truncation of the tower of DSEs is small. A phenomenologically efficacious application of the DSE approach, which employs a parametrisation of the gluon propagator and facilitates the extrapolation application of known properties of QCD at large spacelike-q{sup 2} to the region of small spacelike-q{sup 2}, is discussed and illustrated via the calculation of hadronic observables, such as: {pi}{pi} scattering lengths; pion and kaon electromagnetic form factors; baryon spectroscopy and electromagnetic properties.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 374853
- Report Number(s):
- CONF-9304297-; ISSN 0003-0503; TRN: 96:004080-0228
- Journal Information:
- Bulletin of the American Physical Society, Vol. 40, Issue 2; Conference: 1993 joint meeting of the American Physical Society and the American Association of Physics Teachers, Washington, DC (United States), 12-15 Apr 1993; Other Information: PBD: Apr 1995
- Country of Publication:
- United States
- Language:
- English
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