Probing non-graviton spectra in \( \mathcal{N}=4 \) SYM via BMN truncation and S-duality
摘要
The one-loop cohomology of
We also examine the indices of S-dual pairs SO(2N + 1) and Sp(N) SYM. Although their full 1/16-BPS indices coincide, we find discrepancies in their BMN-sector indices. As the BMN indices restricted to the graviton sector are expected to be the same, this mismatch allows us to identify non-graviton cohomologies. We explicitly find one of them in the SO(7) theory that is responsible for the mismatch of the BMN index. We also show that indices restricted to other one-loop cohomology truncations, in general, do not match under S-duality. If the conjecture of exactness of one-loop cohomology is correct, this suggests the presence of new cohomology sub-rings that match under S-duality with the letter-based truncations of the one-loop cohomology. This offers a way to check the one-loop exactness conjecture.