ar X iv : h ep - p h / 98 11 37 2 v 1 1 7 N ov 1 99 8 INTERFERING QCD / QED VACUUM POLARIZATION
نویسنده
چکیده
Vacuum polarization mediated by quark loops is susceptible to external electromagnetic fields as well as to the QCD vacuum structure. Employing the stochastic vacuum model, we calculate the modification of the one-loop Euler-Heisenberg effective action due to stochastic color fields with the Fock-Schwinger technique. Our results indicate nonperturbative light quark contributions of the same order of magnitude as the usual QED terms. Various theoretical and experimental implications are discussed in this progress report.
منابع مشابه
ar X iv : h ep - p h / 96 11 42 1 v 1 2 6 N ov 1 99 6 SLAC – PUB – 7361 November 1996 QCD : Questions , Challenges , and Dilemmas ∗
An introduction to some outstanding issues in QCD is presented, with emphasis on work by Diakonov and co-workers on the influence of the instanton vacuum on low-energy QCD observables. This includes the calculation of input valence-parton distributions for deep-inelastic scattering.
متن کاملar X iv : h ep - t h / 95 11 19 2 v 1 2 7 N ov 1 99 5 Inhomogeneous Condensates in Planar QED ∗
We study the formation of vacuum condensates in 2 + 1 dimensional QED in the presence of inhomogeneous background magnetic fields. For a large class of magnetic fields, the condensate is shown to be proportional to the inhomogeneous magnetic field, in the large flux limit. This may be viewed as a local form of the integrated degeneracy-flux relation of Aharonov and Casher.
متن کاملar X iv : h ep - p h / 97 11 22 6 v 1 4 N ov 1 99 7 Instantons and Polarized Structure Functions
The contribution of the quark-quark and quark-gluon interaction induced by instantons to the valence quark and proton spin-dependent structure functions g 1 (x, Q 2) is estimated within the instanton liquid model for QCD vacuum. It is shown, that this interaction leads to a rather large violation of the Ellis-Jaffe sum rule.
متن کاملar X iv : h ep - p h / 92 11 30 6 v 1 2 5 N ov 1 99 2 QCD RESULTS FOR NUCLEON COMPTON SCATTERING
We present QCD results for the exclusive processes γN → γN (N = p, n) at large momentum transfer and compare them to data for the proton.
متن کاملar X iv : h ep - p h / 98 07 28 8 v 1 8 J ul 1 99 8 LAPTH - 687 / 98 On the Calculation of QED Amplitudes in a Constant Field
It is explained how first-quantized worldline path integrals can be used as an efficient alternative to Feynman diagrams in the calculation of QED amplitudes and effective actions. The examples include the one-loop photon splitting amplitude, the two-loop Euler-Heisenberg Lagrangian, and the one-loop axial vacuum polarization tensor in a general constant electromagnetic field. Talk given at the...
متن کامل