English

Effective Lagrangians in $2 + \epsilon$ Dimensions

High Energy Physics - Phenomenology 2009-10-31 v3 Condensed Matter High Energy Physics - Theory

Abstract

The failure of the the loop expansion and effective lagrangians in two dimensions, which traditionally hinges on a power counting argument is considered. We establish that the book keeping device for the loop expansion, a role played by (the reciprocal of) the pion-decay constant itself vanishes for d=2d=2, thereby going beyond the power counting argument. We point the connection of our results to the distinct phases of the candidate for the effective lagrangians, the non-linear sigma model, in d=2+ϵd=2+\epsilon, and eventually for d=2d=2. In light of our results, we recall some of the relavant features of the multi-flavor Schwinger and large NfN_f QCD2QCD_2 as candidates for the underlying theory in d=2d=2.

Cite

@article{arxiv.hep-ph/9807356,
  title  = {Effective Lagrangians in $2 + \epsilon$ Dimensions},
  author = {B. Ananthanarayan},
  journal= {arXiv preprint arXiv:hep-ph/9807356},
  year   = {2009}
}

Comments

13 pages plain LaTeX, to be run twice. Replaced with expanded and corrected version. One footnote added

R2 v1 2026-07-22T14:45:03.517Z