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Recent research activities of division of nuclear physics
Cheoun Myung-Ki 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.82 No.6
I review the recent development of research groups of the Division of Nuclear Physics (DNP) in the Korean Physical Society (KPS) during the 2000s for commemorating the 50 year history of the DNP in the KPS. Since detailed research activities in each feld of the DNP are introduced in other papers of this special issue, this review is focused on the main research groups, RISP (Rare Isotope Science Project) for the RAON accelerator, CENS (Center for Exotic Nuclear Studies) in the IBS (Institute of Basic Science) for the application of the RAON accelerator, CENuM (Center for Extreme Nuclear Matters) by the SRC (Scientifc Research Center) Program, OMEG (Origin of Matter and Evolution of Galaxy) Institute by the Key Research Center in Universities Program, and other international research activities.
Asymmetry in the neutrino and anti-neutrino reactions in a nuclear medium
Cheoun, M.K.,Choi, K.S.,Kim, K.S.,Saito, K.,Kajino, T.,Tsushima, K.,Maruyama, T. North-Holland Pub. Co 2013 Physics letters: B Vol.723 No.4
We study the effect of the density-dependent axial and vector form factors on the electron-neutrino (ν<SUB>e</SUB>) and anti-neutrino (ν@?<SUB>e</SUB>) reactions for a nucleon in nuclear matter or in <SUP>12</SUP>C. The nucleon form factors in free space are presumed to be modified for a bound nucleon in a nuclear medium. We adopt the density-dependent form factors calculated by the quark-meson coupling (QMC) model, and apply them to the ν<SUB>e</SUB> and ν@?<SUB>e</SUB> induced reactions with the initial energy E=8-80 MeV. We find that the total ν<SUB>e</SUB> cross sections on <SUP>12</SUP>C as well as on a nucleon in nuclear matter are reduced by about 5% at the nuclear saturation density, ρ<SUB>0</SUB>. This reduction is caused by the modification of the nucleon structure in matter. Although the density effect for both cases is relatively small, it is comparable with the effect of Coulomb distortion on the outgoing lepton in the ν-reaction. In contrast, the density effect on the ν@?<SUB>e</SUB> reaction reduces the cross section significantly in both nuclear matter and <SUP>12</SUP>C cases, and the amount maximally becomes of about 35% around ρ<SUB>0</SUB>. Such large asymmetry in the ν<SUB>e</SUB> and ν@?<SUB>e</SUB> cross sections, which seems to be nearly independent of the target, is originated from the differences in the helicities of ν@?<SUB>e</SUB> and ν<SUB>e</SUB>. It is expected that the asymmetry influences the r-process and also the neutrino-process nucleosynthesis in core-collapse supernovae.
Myung Ki Cheoun,Kyungsik Kim 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.4
We calculated the 2 decay for 96 40Zr56 ! 96 42Mo54 and the Gamow-Teller strength for 96 40Zr56 ! 96 41Nb55 and 96 42Mo54 ! 96 41Nb55 by using the quasi-particle random phase approximation (QRPA). Our QRPA includes all kinds of the nucleon pairing correlations (neutron-neutron, proton-proton, and neutron-proton), which are considered within the extended Bardeen-Cooper-Schrieffer (BCS) theory. The Brueckner reaction matrix is obtained from the Bonn potential through the Bethe- Goldstone equation. The results show reasonable behaviors with respect to the excitation energies.
김유천(You-cheoun Kim) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-
Around two years have passed since the beginning of aptitude test required by 2006 Rail Safety Act. At this point, it is necessary to evaluate the validity of the aptitude test. Through this study, the structural system for all the tests would be overviewed, which will show the correlation among each tests or its importance. Also, although it is rough, reliability and validity of the tests would be overviewed by their retest and education materials. This would contribute, in the future, to setting up for the standard of upgrading or integrating the tests.