Instanton effective action formalism for 2-point and 4-point functions
We provide an instanton effective action formalism in terms of which one can investigate the nonperturbative generation of 2-point and 4-point functions.
hep-ph↗
arXiv subjects
F. S. Roux
Publications and source records attributed to F. S. Roux.
Critical couplings for chiral symmetry breaking via instantons
Using an instanton effective action formalism, we compute the critical coupling for the nonperturbative formation of a dynamical mass via instantons in non-Abelian gauge theories with N_f massless fermions. Only continuous phase transitions are considered. For large values of N_f the critical couplings are found to be much smaller than the equivalent critical couplings obtained from gauge exchange calculations in the ladder approximation.
hep-ph↗
Symmetry breaking via fermion 4-point functions
We construct the effective action and gap equations for nonperturbative fermion 4-point functions. Our results apply to situations in which fermion masses can be ignored, which is the case for theories of strong flavor interactions involving standard quarks and leptons above the electroweak scale. The structure of the gap equations is different from what a naive generalization of the 2-point case would suggest, and we find for example that gauge exchanges are insufficient to generate nonperturbative 4-point functions when the number of colors is large.
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Trouble for MAC
We show that the next-to-leading corrections to the kernel of the gap equation can be large and of opposite sign to the lowest order kernel, in the presence of a gauge boson mass. This calls into question the reliability of the Most Attractive Channel hypothesis.
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