Normalize the <cubic anomaly coefficient> of the $SU(N)$ fundamental to $+1$. The <two-index antisymmetric representation> has anomaly coefficient $N-4$, while an antifundamental contributes $-1$. Cancellation of the $SU(N)^3$ <gauge anomaly> requires
$$
(N-4)-p=0,
\qquad
\boxed{p=N-4}.
$$

Solution

Past exam of the mathematics course of the University of Cambridge / 2022 / iii / Paper 307 / 3 / i / Solution

 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2022/iii/paper-307/3/i/solution