Searches for the Σ-nucleus Potential

The determination of the Σ-nucleus potential is the main orientation of the late Σ-hypernuclear physics. For this purpose, the last (Κ-,π+) light Σ-hypernuclear spectra were studied together with the recent (π-, Κ+)28Si_Σ spectrum in the context of the Green function method with a square well optical potential and a delta function spin-orbit interaction using plane waves. It was found that these spectra with a broad enhancement mainly at large energies are well described by a repulsive potential with nonzero imaginary and spin-orbit parts.

Nucleon structure studies with the PANDA experiment at FAIR

The PANDA experiment is one of the major projects in preparation at the upcoming FAIR facility in Darmstadt, Germany. A multipurpose high energy physics detector is currently under construction and will be operated at the High Energy Storage Ring of FAIR. High intensity antiproton beams will be available in the momentum range between 1.5 GeV/c and 15 GeV/c and will allow to address a broad physics program including hadron spectroscopy, study of charm and strangeness in nuclei, hypernuclear physics and other QCD topics. In addition, the PANDA experiment will offer unique possibilities to investigate the structure of the proton using different electromagnetic processes. In this contribution, the PANDA physics program related to the nucleon structure aspects is discussed. Feasibility studies of electromagnetic processes for the measurements of proton electromagnetic form factors in the time-like region and the nucleon-to-meson transition distribution amplitudes at PANDA, are reported.

Baryon interactions from lattice QCD with physical masses —S = −3 sector: Ξ∑ and Ξ∑-Λ∑—

Hyperon-nucleon and hyperon-hyperon interactions are important in studying the properties of hypernuclei in hypernuclear physics. However, unlike the nucleons which are quite stable, hyperons are unstable so that the direct scattering experiments are difficult, which leads to the large uncertainty in the phenomenological determination of hyperon potentials. In this talk, we use the gauge configurations generated at the (almost) physical point (mπ = 146 MeV) on a huge spatial volume (8:1fm)4 to present our latest result on the hyperon-hyperon potentials in S = −3 sector (Ξ∑ single channel and Ξ∑- ΞΛ; coupled channel) from the Nambu-Bethe-Salpeter wave functions based on the HAL QCD method with improved statistics.