Experimental plan of Σp scatterings at J-PARC

In order to test theoretical frameworks of the baryon-baryon interactions and to confirm the Pauli effect between quarks for the first time, we propose an experiment to measure low-energy hyperon proton scattering cross sections in the following channels with high statistics, 1. Sigma(-)p elastic scattering, 2. Sigma(-)p -> Lambda n inelastic scattering, 3. Sigma(+) p elastic scattering. According to theoretical models based on quark-gluon picture for the short range part of the baryon-baryon interactions, the Sigma(+)p channel is expected to have an extremely repulsive core due to the Pauli effect between quarks, which leads a Sigma(+)p cross section twice as large as that predicted by conventional meson exchange models with a phenomenologically treated short range repulsive core. In addition, measurement of the S-p channel where the quark Pauli effect is not effective is also necessary to test the present theoretical models based on meson exchange picture with the flavor SU(3) symmetry. Thus this experiment will provide essential data to test the frameworks of the theoretical models of the baryon-baryon interactions and to investigate the nature of the repulsive core which has not been understood yet. In order to overcome the experimental difficulties in measuring low-energy hyperon proton scattering, we will use a new experimental technique in which a liquid H2 target is used as hyperon production and hyperon scattering targets with a detector system surrounding the LH2 target for detection of a scattered proton and a decay product from a hyperon. The hyperon scattering event is kinematically identified. Because imaging detectors used in past experiments are not employed, high intensity pi beam can be used, allowing us to take high statistics data of 100 times more than the previous experiments. We have proposed an experiment of Sp scattering at the K1.8 beam line by utilizing the K1.8 beam line spectrometer and the SKS spectrometer. A high intensity p beams of 2x10(7)/ spill at 1.32 GeV/c and 1.42 GeV/c for the S-and Sigma(+) productions, respectively, are used to produce as many hyperon beam as possible. With 16x10(6) Sigma(-)beam and 55x10(6) Sigma(-) beam around 500 MeV/ c which are tagged by the spectrometers, we will detect similar to 10,000 Sigma(-)p and S+ p scattering events and similar to 6,000 Sigma(-)p -> n inelastic reaction events in 60 days beam time in total. In this proceedings, we will present the experimental plan of the scattering experiment and results of the detailed simulation studies.