Friday, July 27, 2018 11:00 LIT, r.310 Prof. Akeo Misaki(Saitama University, Japan) The diversities of cosmic ray phenomena at high and extremely high energies and reliable energy estimation of the phenomena concerned The speaker’s talk deals with cosmic ray phenomena at high (over 1010 - 1012 eV to 1012 - 1015 eV) and extremely high (over 1021 eV), such as high and extremely high energy neutrino physics phenomena, and extensive air showers. Concretely speaking,the range energy fluctuation of high energy muon which plays an important role in high and extremely high energy muon astrophysics physics over 1015 eV to 1015 eV is discussed. The diversity of the electromagnetic cascade showers at extremely high energies (1023 eV to 1023 eV) is analyzed for the its application to extremely high energy electron neutrino astrophysics. The energy estimation of extensive air showersis considered, too. The importance of the exact treatment to the stochastic processes in cosmic ray phenomena at high and extremely high energies is strongly emphasized. Such exact treatments to stochastic processes in the cosmic ray phenomena have not been adopted due to time consuming, frequently, which may lead to unreliable conclusion. The speaker would explain the background for the collaboration with Drs. Olga Voskresenskaya and Hrach Torosyan in his seminar.