The Analysis Status of $${\varSigma }^+ p$$ Σ + p Scattering Events in the J-PARC E40 Experiment

The J-PARC E40 experiment aims for measuring cross sections of the $${\varSigma } p$$ scatterings with high statistics by overcoming difficulties of hyperon-nucleon scattering experiment. The physics motivations are to verify the large repulsive force due to quark Pauli effect in the $${\varSigma }^+ p$$ interaction and to perform systematic study of the $${\varSigma } N$$ interaction. Physics data taking was performed at the K1.8 beam line in the J-PARC hadron experimental facility by 2020 June. $${\varSigma }^+$$ particles were produced via the $$\pi ^+ p \rightarrow K^+ {\varSigma }^+$$ reaction and their momenta were tagged with spectrometers. Recoil proton of the $${\varSigma }^+p$$ scatterings and proton from the $${\varSigma }^+ \rightarrow p \pi ^0$$ decay were detected with surrounding detector system CATCH. The $${\varSigma }^+ p$$ scattering can be identified by checking the consistency for the recoil proton between the measured energy and the calculated energy from kinematics of the $${\varSigma }^+ p$$ scattering . In present analysis, 69M $${\varSigma }^+$$ particles are tagged as the $${\varSigma }^+$$ beam and 4500 $${\varSigma }^+ p$$ scattering events are identified. Further analysis to derive the differential cross sections is ongoing.