Speaker
Description
The Quantum Observables approach to High Energy Physics is an emerging framework in which observables borrowed from Quantum Information theory are used to test the Standard Model and explore BSM Physics. This methodology received experimental validation in 2023-2024, when the ATLAS and CMS collaborations reported measurements, via quantum tomography, of entanglement in $t\bar{t}$ pairs produced at the LHC. Existing studies treat fermion pairs as closed quantum systems, neglecting their interactions with the surrounding environment. In our work, we relax this assumption by modelling fermion pairs as open quantum systems, allowing interactions with the surroundings. This framework enables the study of decoherence effects, arising from uncontrolled and unobserved interactions between system and environment, that spoil the quantum properties we aim to probe, e.g. entanglement, possibly impacting the comparison between predictions and measurements. Our initial results, obtained for the decay of a massive scalar boson into a $t\bar{t}$ pair, indicate that environmental interactions lead to a reduction of entanglement. We are currently extending this analysis to fermion pairs produced in $e^+e^-$ collisions, with future plans to investigate the pp collision.