Programme

O.15 -- Oral, VCTP-51

Date: Tuesday, 4 August 2026

Time: 11:30 - 11:50

Testing Maximal Leggett–Garg Inequality Violation with Two-Detector Accelerator-Based Neutrino Experiments

Tran Van Ngoc (1), Cao Van Son (1), Quach Khanh Duc (2)

(1) International Centre for Interdisciplinary Science and Education (ICISE);(2) University of Science and Technology of Hanoi (USTH)

The Leggett–Garg Inequality (LGI) provides a powerful framework for testing macroscopic realism and quantum coherence through temporal correlations. Neutrino oscillations, which maintain quantum coherence over macroscopic distances, offer a unique laboratory for investigating these fundamental aspects of quantum mechanics. In this work, we present a systematic study of LGI violations in neutrino oscillations. By expressing the LGI parameter in terms of oscillation phases, we construct a phase-space representation of the violation landscape and identify the optimal baseline configuration $L_3 = 2L_2$, suggesting a two-detector configuration for accelerator-based experiments for testing maximal LGI violation. We further investigate the dependence of the maximal LGI violation on the atmospheric mixing angle and find that the optimum occurs close to maximal atmospheric mixing. This observation highlights a unique feature of neutrino oscillations in testing the maximal violation of LGI. To assess experimental feasibility, we perform a study using Hyper-Kamiokande simulation data, incorporating realistic backgrounds and statistical uncertainties. Our results demonstrate that the predicted LGI violation remains robust under full three-flavor oscillations, across different $\theta_{23}$ octants, and in the presence of background contamination. These findings establish a quantitative framework for future LGI measurements in long-baseline neutrino experiments and highlight the potential of Hyper-Kamiokande to probe the foundations of quantum mechanics on macroscopic scales.

Presenter: Tran Van Ngoc