2023/05/09 by Mohammad Mahdi Altakach, Priyanka Lamba, Fabio Maltoni +2 · 10 citations
Physics and Astronomy · #Particle physics theoretical and experimental studies #Dark Matter and Cosmic Phenomena #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.1103/physrevd.107.093002
We introduce a methodology and investigate the feasibility of measuring quantum properties of tau lepton pairs in the H\ensuremath→\ensuremathτ+\ensuremathτ^\ensuremath- decay at future lepton colliders. In particular, observation of entanglement, steerability, and violation of Bell inequalities are examined for the International Linear Collider (ILC) and Future Circular e+e^\ensuremath- Collider (FCC-ee). We find that detecting quantum correlation crucially relies on precise reconstruction of the tau lepton rest frame, and a simple kinematics reconstruction does not suffice due to the finite energy resolution of the colliding beams and detectors. To correct for energy mismeasurements, a log-likelihood method is developed that incorporates the information of impact parameters of tau lepton decays. We demonstrate that an accurate measurement of quantum properties is possible with this method. As a by-product, we show that a novel model-independent test of CP violation can be performed and the CP phase of H\ensuremathτ\ensuremathτ interaction can be constrained with an accuracy comparable to dedicated analyses, i.e., up to 7.9\ifmmode^∘\else\textdegree\fi and 5.4\ifmmode^∘\else\textdegree\fi at ILC and FCC-ee, respectively.