Study Of J/???(?) At STCF And Measurement Of ? Form Factors At BES?

Hyperon non-lepton decay has played an important role in understanding CP violation in particle physics.So far,the asymmetry decay parameters of CP violation for A-decays had been measured with many highly sensitive experiments.However,the uncertainty for the measured asymmetry parameters are still too large.The University of Science and Technology of China together with other groups have proposed to build a new generation collider in China with higher luminosity--Super Tau-Charm Facility(STCF).The larger data will be got with the STCF detector which will help to further understanding the nature of the CP violation.The STCF is still in the pre-research stage.The first chapter of this work used the fast simulation software package to simulate the physical process J/???(?)?p?-n?0 to provide optimization indicators for the STCF detector design.And based on 1T data statistics,the accuracy of CP violation on STCF is pre-studied up to 10-4.In addition,nucleons are the most important component of observable matter in the universe,and had been proven to be non-point particles in the middle of the last century.However,the properties of nucleons,such as radius,spin,polarization,etc.,are far from being well understanding.Hyperons provide other new perspective in further understanding the structure of nucleons,since they have similar quark components.In the second chapter of this work provides the study of e+e-??+?at center of mass energy of 2.644 GeV with the data obtained with the new highluminosity energy scan performed by BES? detector.With a statistical significance of 3.58?,the relative phase of the electromagnetic form factors of ? is measured at 51.80°± 17.420 for the first time.