Speaker
Description
Final state hard radiation of photons or gluons is a critical NLO phenomena to consider at high energy colliders since it can change the kinematics and physics probed. In the maturing field of quantum information at colliders there has been an increased interest in investigating the effect of radiation on the bipartite spin entanglement of fermion pairs. Within this quantum information framework, the final state radiation can be seen as interaction with environmental degrees of freedom leading to decoherence of the fermion pair. We study the radiative decay of the Z boson: $Z \rightarrow \tau^- \tau^+ \gamma$ as an illustrative example for exploring decoherence. We consider the complete 3-body kinematics and explore various quantum information observables to quantify the decoherence effect on the tau pair bipartite system. Interestingly, we find hard photon radiation does not always reduce the fermion pairs’ entanglement and there even exists phase space where the photon can increase the entanglement of the fermions.