Comments on QCD$_3$ and anomalies with fundamental and adjoint matter

• Main Authors: Lohitsiri, Nakarin, Sulejmanpasic, Tin
• Format: Journal Article
• Language: English
• Published: 16.05.2022
• Subjects: Physics - High Energy Physics - Theory
• DOI: 10.48550/arxiv.2205.07825

't Hooft anomaly matching is powerful for constraining the low energy phases of gauge theories. In 3d one common anomaly is the parity anomaly in a $T$-symmetric theory where one cannot gauge the global symmetry group without breaking the time-reversal symmetry. We find that a $T$-symmetric $\text{SU}(N)$ gauge theory with either fermionic or bosonic matter in the fundamental representation of the gauge group has a parity anomaly between the flavor group and $T$-symmetry provided that there is also a massless Majorana fermion in the adjoint representation of the gauge group. We then analyze the parity anomaly in this theory, together with the more recent mod 16 time-reversal anomaly, and give some free fermion proposals as candidates for the low energy phases consistent with the anomalies. We make brief comments about the large $N$ limit and the $\T$-broken regimes in the conclusion as well as related anomalies in 4d. }