The Bell nonlocality and entanglement are two kinds of quantum correlations in quantum systems. Due to the recent upgrade in the Beijing Spectrometer III (BESIII) experiment, it is possible to explore the nonlocality and entanglement in hyperon-antihyperon systems produced in electron-positron annihilation with high precision data. We provide a systematic method for studying quantum correlations in spin-$1/2$ hyperon-antihyperon systems through the measures for the nonlocality and entanglement. We find that with nonvanishing polarizations of the hyperon and its antihyperon, the kinematic region of nonlocality in the hyperon-antihyperon system is more restricted than the ${\tau }^{+}{\tau }^{-}$ system in which polarizations of $\tau$ leptons are vanishing. We also present an experimental proposal to probe the nonlocality and entanglement in hyperon-antihyperon systems at BSEIII.

For over 100 y, scientists have investigated the properties of the proton, which is one of the most abundant components of visible matter in the universe. Nevertheless, researchers do not fully understand many details about its internal structure and dynamics. Time-like electromagnetic form factors are some of the observable quantities that can help us achieve a deeper understanding. In this review article, we present an overview of the current experimental status in this field, consisting of measurements of the time-like reactions $e^{+}{e}^{-}\to p\overline{p}$ and $p\overline{p}\to e^{+}{e}^{-}$ and future measurements of $p\overline{p}\to {\mu }^{+}{\mu }^{-}$. The focus is put on recent high-precision results of the reaction $e^{+}{e}^{-}\to p\overline{p}$ that have been obtained after analyzing 688.5 pb${}^{-1}$ of data taken at the BESIII experiment. They are compared to and put into perspective with results from previous measurements in this channel. We discuss the channels $p\overline{p}\to e^{+}{e}^{-}$ and $p\overline{p}\to {\mu }^{+}{\mu }^{-}$ in terms of the few existing, as well as future measurements, which the PANDA experiment will perform. Finally, we review several new theoretical models and phenomenological approaches inspired by the BESIII high-precision results and then discuss their implications for a deeper understanding of the proton’s structure and inner dynamics.

Exclusive hyperon-antihyperon production provides a unique insight for understanding of the intrinsic dynamics when strangeness is involved. In this paper, we review the results of $\Lambda \overline{\Lambda }$ production via different reactions from various experiments, e.g., via $\overline{p}p$ annihilation from the LEAR experiment PS185, via electron-positron annihilation using the energy scan method at the CLEO-c and BESIII experiments and the initial-state-radiation approach utilized at the BaBar experiment. The production cross section of $\Lambda \overline{\Lambda }$ near the threshold is sensitive to QCD based prediction. Experimental high precision data for $\overline{p}p\to \overline{\Lambda }\Lambda$ close to the threshold region is obtained. The cross section of $e^{+}{e}^{-}\to \Lambda \overline{\Lambda }$ is measured from its production threshold to high energy. A non-zero cross section for $e^{+}{e}^{-}\to \Lambda \overline{\Lambda }$ near threshold is observed at BaBar and BESIII, which is in disagreement with the pQCD prediction. However, more precise data is needed to confirm this observation. Future experiments, utilizing $\overline{p}p$ reaction such as PANDA experiment or electron-positron annihilation such as the BESIII and BelleII experiments, are needed to extend the experimental data and to understand the $\Lambda \overline{\Lambda }$ production.

We report a feasibility study of CP violation of τ^-→Κ_Sπ^-ν_τ decay at a Super Tau Charm Facility (STCF). With an expected luminosity of 1 ab^-1 collected by STCF per year at a center-of-mass energy of 4.26 GeV, the statistical sensitivity for the CP violation is determined to be of order 9.7×10^-4 by measuring the decay-rate difference between τ⁺→Κ_Sπ⁺ν_τ and τ^-→Κ_Sπ^-ν_τ. The analysis is performed using a reliable fast simulation software package, which can describe the detector responses properly and vary the responses flexibly for further optimization. Moreover, the energy-dependent efficiencies for reconstructing τ^-→Κ_Sπ^-ν_τ are presented and the expected CP sensitivity is proportional to 1/√L in the energy region from 4.0 to 5.0 GeV. The sensitivity of CP violation is of order 3.1×10^-4 with 10 ab^-1 integrated luminosity, which is equivalent to ten years data taking in this energy region at STCF. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Electromagnetic form factors (EMFFs) are fundamental observable of baryons that intimately related to their internal structure and dynamics, where the EMFFs of hyperons provide valuable insight into the behavior of the strangeness. The EMFFs of hyperons can also help to understand those of nucleons as they are connected with the flavor SU(3) symmetry. The EMFFs of nucleons can be measured in both spacelike and timelike regions. However, it is difficult to probe the EMFFs of hyperons in spacelike region due to the unstable nature of hyperons. By means of electron-positron annihilation, the EMFFs of hyperons in timelike region is accessible via the production of hyperon-antihyperon pair. The timelike EMFFs of the isospin triplet $\Sigma$ hyperons measured at Babar, CLEO-c and BESIII experiments are reviewed in this paper. Besides, the relevant theoretical discussion based on the experimental results are also presented.