Exploring Bell inequalities and quantum entanglement in vector boson scattering

Abstract

Quantum properties of vector boson scattering $V'_1V'_2\to V_1 V_2$, related to entanglement and violation of Bell inequalities, are explored in this paper. The analysis is based on the construction of the polarization density matrix associated to the final state $V_1V_2$ by means of the computation of the corresponding tree level amplitudes within the Standard Model. The aim of this work is to determine the regions of the phase space where the final vector bosons after the scattering result entangled and if is it possible to test the Bell inequalities in those regions. We found that in all cases the entanglement is present. The amount of it depends on the process and the Maximally Entangled state is reached in some particular channels. Concerning the Bell inequality, it could be also tested in certain kinematical regions for some of these processes. This work is a first step in the analysis of these quantum properties for this kind of processes and it is postponed for future studies the reconstruction of the polarization density matrix and the related quantum parameters from experimental data through Monte-Carlo simulations using quantum tomography techniques.