Study of hadron structure and exotic hadron in the COMPASS experiment

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This research has aimed to study the precise quark-gluon structure of nucleon and to search exotic hadrons and reaction processes by using the Super Proton Synchrotron as the COMPASS international collaboration at CERN. We collected enough data with polarized moon beam and polarized target and analyzed data Finally we have extracted spin-dependent structure functions of deuteron to highly precise extent. The measured structure functions of deuteron are summarized as 1) transversely polarized quark distribution, 2) longitudinally polarized gluon distribution, 3) longitudinally polarized quark distribution. We presented results at domestic and international meetings and published at international journals. Especially the 1) and 2) were the first data in the world and the 3) was improved precision of the measured data which contributed greatly to development of study of nucleon structure. Our result concerning gluon suggests small contribution of gluon to the nucleon spin which was not an … More ticipated before and this result is also consistent with the other experimental results with proton target such as the HERMES collaboration results at DESY and the RHIC collaboration results at BNL. Our result using transversely polarized deuteron shows almost zero distributions of Collins and Sivers functions at deuteron. This result impacts on the understanding of orbital angular momentum of quark and gluon inside nucleon because its smallness suggests a small or zero contribution of gluon orbital angular momentum to the nucleon spin. We also carried out the transversely polarized proton experiment which is attracted an attention in the world because the only measurement carried by the HERMES experiment showed non-zero Collins and Sivers distributions and the results are strongly needed to be confirmed. We also prepare a next experiment using hadron beam and construct a liquid proton target. We also considered experimental and theoretical issues for the hadron beam experiment and studied to clarify the problems of exotic meson. Less