Probing multiparameter quantum estimation in the process $e^+e^-\to J/\psi \to \text{B}\bar{\text{B}}$ at BESIII

TL;DR

This paper explores the use of quantum Fisher information to optimize multiparameter estimation of physical parameters in baryon-antibaryon pairs produced at BESIII, revealing how sensitivity varies with parameters and environmental effects.

Contribution

It applies the QFIM framework to a realistic particle physics process, analyzing optimal estimation strategies and the impact of decoherence on measurement precision.

Findings

Higher true parameter values increase sensitivity and reduce variance.

Estimation variances grow over time but at different rates depending on the parameter.

Environmental decoherence affects the information loss and precision limits.

Abstract

The quantum Fisher information matrix (QFIM) is the cornerstone of multiparameter quantum metrology. In this work, we investigate multiparameter quantum estimation in baryon-antibaryon (B bar-B) pairs produced via the e+ e- -> J/psi -> B bar-B process at the BESIII experiment, utilizing the symmetric logarithmic derivative (SLD) formalism. Moreover, the QFIM defines the quantum Cramer-Rao bound and dictates the choice of optimal probe states. We compare individual and simultaneous estimation strategies for two key physical parameters: the scattering angle phi and the decay parameter alpha_psi. The estimation variances are found to depend strongly on the explored region of the (phi, alpha_psi) parameter space and to display markedly different temporal dynamics. In general, higher true values of a parameter increase the system's sensitivity, thereby significantly reducing the associated variance. While both variances increase with evolution time, they do so at distinct rates, revealing parameter-dependent information loss driven by environmental decoherence. These findings demonstrate the utility of the QFIM framework for multiparameter quantum estimation in realistic open systems and provide new insights into the ultimate precision limits achievable for hyperon decay parameters.