Dr. Prisco Lo Chiatto

T a l k : 26. June 2025

A Quantum Observable for a Quantum Phenomenon? Measuring tau Dipoles with Resurrection

Abstract

Quantum information is currently experiencing a resurgence of interest in collider physics, thanks to observables that quantify the amount of entanglement created in particle collisions. It is a natural question to ask whether these observables are a good probe for physics beyond the Standard Model (SM). To investigate this, we focus on 4-fermion scattering. We consider the effect of SM effective field theory (SMEFT) operators whose interference with the SM does not contribute to the cross section, thereby reducing experimental reach. In such cases, sensitivity can be greatly improved by considering spin correlations that "resurrect" the interference. This leads to the tantalising prospect that the quantum phenomenon of interference resurrection could be probed by a quantum observable. Contrary to expectations, we find that re-interpreting spin correlations as quantum information observables leads to worse sensitivity to SMEFT operators. Moreover, this procedure erases information about CP violation.