Colliders in the Sky: Constraining High-Energy Physics with Cosmological Observations

by Prof. Oliver Philcox (Stanford University)

Friday 9 Oct 2026, 12:30 → 14:30 America/Los_Angeles

48/2-224 - Madrone (SLAC)

With an energy scale potentially reaching 10^15 GeV, the physical description of inflation likely lies far beyond the realm of the standard model. This leaves many questions unanswered: what fields were present during inflation? how did they interact with each other? In this seminar, I will discuss how modern cosmological datasets can be used to shed light on the early Universe by searching for the tell-tale signs of “primordial non-Gaussianity”. In particular, I will present new searches for inflationary signals in Cosmic Microwave Background and galaxy survey data, which allow for a detailed study of the primordial effective Lagrangian. Leveraging an array of theoretical and computational tricks, these methods can place constraints on the microphysics of inflation and directly probe particle scattering processes in the early Universe, practically acting as a “cosmological collider”.