Post #525764

Tuesday's #paperOfTheDay is related to the one about 4-fermion coupling a few days ago. Indeed, "The equivalence of the top quark condensate and the elementary Higgs field" from 1991 essentially deals with the same setup: They consider a #quantumFieldTheory with 4-fermion interaction in 4 dimensions, which is not renormalizable by power counting, but can be treated in the leading large-N limit. The conclusion is that in this limit, the theory can be solved more or less explicitly, and its low-energy predictions are indistinguishable from having a scalar "Higgs" particle. In that scenario, whether or not the Higgs is a fundamental scalar particle is merely a question of definitions, rather than a meaningful physical one. The leading large-N limit is not necessarily an accurate description of the full physical theory (in the same way that the first coefficient of a small-g expansion, i.e. a 1-loop calculation, is not). I would be interesting to know what the current understanding of 4-fermion interactions in 4 dimensions is, surely by now we must have many more theoretical and numerical calculations. https://www.sciencedirect.com/science/article/abs/pii/055032139190607Y