Electroweak corrections to Bell inqualities and entanglement in H → ZZ processes at the LHC

This work explores the quantum properties of the system formed by heavy vector bosons originating from the Higgs boson decay. High-energy physics processes exhibit non-classical correlations, like any quantum system, but detecting such behavior remains a significant challenge. The Higgs boson is a natural candidate for these studies: as a scalar particle with spin 0, the state of its decay products is often close to maximal entanglement. We focus on the process H → ZZ with a fully leptonic final state, analyzing it from a quantum information perspective. Our goal is to identify entanglement markers and observables that signal violations of Bell inequalities. We compute quantum observables within the Standard Model, incorporating Next-to-Leading Order (NLO) electroweak corrections. In specific cases, we find that NLO effects significantly impact the extraction of quantum correlation parameters. Several regions of phase space are investigated, in order to interpret the results obtained. Our results suggest that the dominant source of large NLO corrections stems from modifications to the spin-analyzing power, affecting the tomographic reconstruction of the quantum state. Finally, we conduct a study of potential new physics effects in the Higgs sector and examine their impact on quantum observables.