Speaker
Description
The Born rule is a central postulate of quantum mechanics and underlies all probabilistic predictions in collider physics, yet direct experimental tests of this assumption have largely been confined to low-energy systems. In this work, we investigate how spin and polarization measurements at high-energy colliders can probe the Born rule at TeV energies. Focusing on experimentally accessible processes at the LHC, including tau-lepton polarization in $Z \rightarrow \tau\tau$ events, we show how helicity cross sections and polarization fractions can be reinterpreted as explicit tests of the Born rule for a two-state system. This perspective naturally connects to ongoing spin-density-matrix and quantum entanglement measurements in processes such as $H \rightarrow ZZ$, where the joint density matrix of the two $Z$ bosons is reconstructed from angular correlations in their leptonic decays. We then outline how future photon polarimetry in radiative top processes could extend such tests to both ensemble polarization measurements and, ultimately, to individual high-energy photons.