We introduce a methodology and investigate the feasibility of measuring quantum properties of tau lepton pairs in the H→τ+τ- 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- 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 Hττ interaction can be constrained with an accuracy comparable to dedicated analyses, i.e., up to 7.9° and 5.4° at ILC and FCC-ee, respectively.

Altakach, M.M., Lamba, P., Maltoni, F., Mawatari, K., Sakurai, K. (2023). Quantum information and CP measurement in H → τ+τ− at future lepton colliders. PHYSICAL REVIEW D, 107(9), 1-15 [10.1103/physrevd.107.093002].

Quantum information and CP measurement in H → τ+τ− at future lepton colliders

Lamba, Priyanka;Maltoni, Fabio;
2023

Abstract

We introduce a methodology and investigate the feasibility of measuring quantum properties of tau lepton pairs in the H→τ+τ- 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- 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 Hττ interaction can be constrained with an accuracy comparable to dedicated analyses, i.e., up to 7.9° and 5.4° at ILC and FCC-ee, respectively.
2023
Altakach, M.M., Lamba, P., Maltoni, F., Mawatari, K., Sakurai, K. (2023). Quantum information and CP measurement in H → τ+τ− at future lepton colliders. PHYSICAL REVIEW D, 107(9), 1-15 [10.1103/physrevd.107.093002].
Altakach, Mohammad Mahdi; Lamba, Priyanka; Maltoni, Fabio; Mawatari, Kentarou; Sakurai, Kazuki
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/959136
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