Instanton partition function near the special vacuum in SU(N) SQCD

by Ekaterina Sysoeva (Universita di Torino)

Friday 17 Oct 2025, 14:00 → 15:00 Europe/Rome

Aula Grassano

We study the instanton partition function in SU(N) theory with 2N fundamental matter multiplets in the vicinity of the so-called special vacuum, where the vacuum expectation values of the Higgs field are arranged near the vertices of a regular N-gon. We begin by investigating the asymptotic behaviour of this function as the diameter of the polygon tends to infinity, which allows us to derive a Zamolodchikov-like recurrence relation. A notable feature of this asymptotic form is the natural emergence of a unique effective coupling constant, seemingly at odds with the known prediction that this theory should involve [N/2] coupling constants. We resolve this apparent contradiction by reconstructing the coupling matrix completely. We then explain why only one of the [N/2] independent coupling constants plays the distinguished role and proceed to study the modular properties of the full set.
Based on arXiv:2507.20876 and further work.