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Perturbative QCD with Quark and Gluon Condensates

Paul Hoyer
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Abstract

The quark <\barψψ> and gluon vacuum expectation values are non-vanishing at low orders in α_s when the perturbative ground state includes quark and gluon pairs. This offers possibilities of studying the effects of a non-trivial vacuum using formally exact perturbative methods. The QCD Feynman rules are modified only for the free, on-shell quark and gluon propagators at zero four-momentum. Gauge and lorentz invariance is maintained, while chiral symmetry is spontaneously broken by the ground state.

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Paul Hoyer. 2002-09-26. Perturbative QCD with Quark and Gluon Condensates. https://arxiv.org/abs/hep-ph/0209318

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