Apparently noninvariant terms of $U(N)\times U(N)$ nonlinear sigma model in the one-loop approximation
High Energy Physics - Theory
2014-11-20 v2
Abstract
We show how the Apparently Noninvariant Terms (ANTs), which emerge in perturbation theory of nonlinear sigma models, are consistent with the nonlinearly realized symmetry by employing the Ward-Takahashi identity (in the form of an inhomogeneous Zinn-Justin equation). In the literature the discussions on ANTs are confined to the SU(2) case. We generalize them to the U(N) case and demonstrate explicitly at the one-loop level that despite the presence of divergent ANTs in the effective action of the "pions", the symmetry is preserved.
Keywords
Cite
@article{arxiv.0907.5260,
title = {Apparently noninvariant terms of $U(N)\times U(N)$ nonlinear sigma model in the one-loop approximation},
author = {Koji Harada and Hirofumi Kubo and Yuki Yamamoto},
journal= {arXiv preprint arXiv:0907.5260},
year = {2014}
}
Comments
two paragraphs added in Introduction, typos in Eqs. fixed