High Energy Elementary Particle and Nuclear Reactions

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On the basis of the standard model on Quantum Chromodynamics (QCD) in particle physics and the quark-gluon degree of freedom in nuclei we extensively discussed high energy particle reactions including those in the early universe and electron-position annihilation reactions.1. Quark-gluon plasma [1,2] In high energy nuclear collisions a very high-temperature and -density state is realized and the phase transition between quark-gluon and hadron phases. We studied that how hadron masses are affected by a change of dynamical properties due to the phase transition. Furthermore, we discussed properties of the non-confinement transition through the topological charge distribution, magnetic structure and fermion zero-modes by simulating lattice gauge fields.2. Skyrme model and related topics [3,4,5] The structure of Skyrme model was investigated in the framework of the quantization of nonlinear theories. We also successfully attempted to extend the Skyrme model to include the strangeness degree of freedom by the collective coordinate method. This approach shed a light on the baryon-baryon interactions and gave a possibility to describe reasonably rta or KAPPA exchange part of NU LAMBDA and NU SIGMA potentials.3. Multiparticle production [6] We proposed a quark-diquark cascade model which enables us coherently to understand distributions of mesons and baryons in the fragmentation region. Also we completed a comprehensive review article on multiparticle dynamics from electron-positron annihilation to nucleus-nucleus collisions.4. Physics at HERA [7,8] The electromagnetic radiative corrections were calculated at the level of 0.01% to e^-p->e^-X at HERA energies. Superpartner production processes e^-p->e^-qX, e^-p->e^-7 qX and e^-p->gamma nu qX were discussed by putting emphasis on how to extract signals by minimizing noises coming from respective backgrounds.