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arXiv · 2106.06402

On Discrete Anomalies in Chiral Gauge Theories

Philip Boyle Smith·Avner Karasik·Nakarin Lohitsiri·David Tong
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Abstract

We study two well-known $SU(N)$ chiral gauge theories with fermions in the symmetric, anti-symmetric and fundamental representations. We give a detailed description of the global symmetry, including various discrete quotients. Recent work argues that these theories exhibit a subtle mod 2 anomaly, ruling out certain phases in which the theories confine without breaking their global symmetry, leaving a gapless composite fermion in the infra-red. We point out that no such anomaly exists. We further exhibit an explicit path to the gapless fermion phase, showing that there is no kinematic obstruction to realising these phases.

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Philip Boyle Smith, Avner Karasik, Nakarin Lohitsiri, David Tong. 2021-06-11. On Discrete Anomalies in Chiral Gauge Theories. https://arxiv.org/abs/2106.06402

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