Counting parity-violating local S-matrices

Abstract: Four point tree-level local S-matrices form a module over ring of polynomials of mandelstam invariants s, t and u. The module of local analytic S-matrices can be encoded in terms of a partition function which is enumerated using plethystic techniques. In this paper, we enumerate the plethystic contribution to local four point photon, graviton and gluon multi-particle partition functions that encode parity violating $2 \rightarrow 2$ scattering. We generalise the counting problem solved in \cite{ Chowdhury:2019kaq, Chowdhury:2020ddc} to project out parity violating sectors, a subtle task in even dimensions \cite{Henning:2017fpj}. We explicitly enumerate the parity odd contributions to the multi-letter partition function for gauge fields, gravitons and gluons and evaluate the resulting parity violating partition functions in $D=4,6$. We also perform a large $D$ analysis to show that parity violating local interactions do not contribute to four particle scattering in higher dimensions ($D\geq 8$). Our computations and observations for photons, gravitons and gluons agree with the transformation properties of these S-matrices previously conjectured in \cite{Chowdhury:2019kaq, Chowdhury:2020ddc}