Radiation effects on the entanglement of fermion pairs at colliders

TL;DR

This paper explores how radiation affects the entanglement of fermion pairs produced at colliders, showing that energetic radiation can cause decoherence and that this effect is observable with current collider data.

Contribution

It provides predictions and experimental feasibility analysis for observing radiation-induced decoherence of fermion pair entanglement at colliders.

Findings

Energetic radiation reduces entanglement of fermion pairs.

Observable decoherence signals are feasible with current collider data.

Future colliders can extend the detection prospects.

Abstract

We study the impact of radiation on quantum systems defined by the spins of elementary fermion-antifermion pairs produced at colliders. We present predictions for several processes, showing that energetic final-state radiation can induce decoherence and significantly reduce the entanglement of quantum systems formed by elementary fermion pairs. We investigate the feasibility of observing this effect experimentally in exclusive samples with energetic radiation. A statistically significant signal can be obtained with current data in associated $pp \rightarrow t\bar{t}(g)$ production at the LHC and in $e^+e^- \rightarrow \tau^{+}\tau^{-}(\gamma)$ production at Belle 2. Future electron-positron colliders operated at the $Z$ pole or well above the $t\bar{t}$ production threshold will extend these prospects further.