The Conformal Anomaly of M5-Branes
Travis Maxfield, Savdeep Sethi
TL;DR
The paper addresses the cubic growth of the conformal anomaly for the six-dimensional $(2,0)$ theory on N M5-branes by examining the Coulomb branch effective action. It develops a two-step approach: first relate the four-derivative couplings on $ ext{R}^{3,1} imes T^2$ to one-loop exact four-dimensional $ ext{N}=4$ SYM results, then deduce the six-derivative couplings from these data. Through detailed analysis of eight-fermion terms and their SUSY constraints in both 6d and 4d, and by matching torus compactifications, the authors show that the relevant four- and six-derivative couplings are controlled by a common constant, and that the six-dimensional anomaly scales as $N^3$ for rank-$N$ theories. The results provide a field-theoretic route to the $N^3$ growth, consistent with holographic expectations and anomaly inflow, and illuminate the structure of higher-derivative interactions in the $(2,0)$ theory.
Abstract
We show that the conformal anomaly for N M5-branes grows like $N^3$. The method we employ relates Coulomb branch interactions in six dimensions to interactions in four dimensions using supersymmetry. This leads to a relation between the six-dimensional conformal anomaly and the conformal anomaly of N=4 Yang-Mills. Along the way, we determine the structure of the four derivative interactions for the toroidally compactified (2,0) theory, while encountering interesting novelties in the structure of the six derivative interactions.
