Λ polarization measurement of the

We performed the J-PARC E40 experiment to measure the Σp scattering cross sections from 2018 to 2020. Together with the π−p → K+Σ− data, the π−p → K0Λ data were accumulated as a byproduct. The analysis confirmed that Λ could be identified with an S/N ratio of ∼ 2.67. The polarization of Λ(PΛ) was preliminarily derived as 1.009 ± 0.049 for the K0 angular range of 0.7 < cos θK0, CM < 0.8. It is more accurate than the past data [1]. The high polarization enables us to measure not only the differential cross section but also spin observables of the Λp scattering in the future J-PARC experiment

Recent progress and future prospects of hyperon nucleon scattering experiment

International audienceA new hyperon-proton scattering experiment, dubbed J-PARC E40, was performed to measure differential cross sections of the Σ+p, Σ−p elastic scatterings and the Σ−p → Λn scattering by identifying a lot of Σ particles in the momentum ranging from 0.4 to 0.8 GeV/c produced by the π±p → K+Σ± reactions. We successfully measured the differential cross sections of these three channels with a drastically improved accuracy with a fine angular step. These new data will become important experimental constraints to improve the theories of the two-body baryon-baryon interactions. Following this success, we proposed a new experiment to measure the differential cross sections and spin observables by using a highly polarized Λ beam for providing quantitative information on the ΛN interaction. The results of three Σp channels and future prospects of the Λp scattering experiment are described

Strangeness physics programs by S-2S at J-PARC

In the K1.8 beam-line at Hadron Experimental Facility of J-PARC, a new magnetic spectrometer S-2S is being installed. S-2S was designed to achieve a high momentum resolution of Δp/p = 6 × 10−4 in FWHM. Several strangeness-physics programs which require the high resolution will be realized by S-2S. The present article introduces J-PARC E70 (missing-mass spectroscopy of Ξ12Be) and E94 (missing-mass spectroscopy of Λ7Li, Λ10B, and Λ12C) experiments