Locality in collider tests of Quantum Mechanics with top quark pairs

TL;DR

This paper discusses the importance of space-like separation in collider experiments testing quantum properties of top quark pairs, proposing criteria to address the locality loophole in such high-energy tests.

Contribution

It introduces criteria considering space-like separation for quantum measurements in collider tests of top quark pairs, addressing the locality loophole.

Findings

Derived bounds for different measurement definitions

Analyzed the impact of space-like separation on quantum tests

Proposed criteria for future collider experiments

Abstract

Tests of quantum properties of fundamental particles in high energy colliders are starting to appear. However, such experiments may suffer from the locality loophole. We argue for criteria that take into account the space-like separation between measurements for the case of spin correlations in top quark pairs produced at the LHC. We derive bounds considering three different definitions of what constitutes the quantum measurement - the decay of top quarks, the decay of W bosons, and the stable decay products contacting a macroscopic device.