EPJ Web Conf.
Volume 219, 2019International Workshop on Particle Physics at Neutron Sources (PPNS 2018)
|Number of page(s)||6|
|Section||Searches for Time-Reversal-Violation in Nuclei|
|Published online||12 December 2019|
Measurement of the angular distribution of γ-rays after neutron capture by 139La for a T-violation search
1 J-PARC center, Japan Atomic Energy Agency, Tokai, Ibaraki 319–1184, Japan
2 Department of Physics, Nagoya University, Furocho, Chikusa, Nagoya, Aichi 464–8601, Japan
3 Kobayashi-Maskawa Institute, Nagoya University, Furocho, Chikusa, Nagoya, Aichi 464–8601, Japan
4 National Institute of Standards and Technology, 100 Bureau Dr, Gaithersburg, MD 20899, USA
5 Department of Physics, Kyushu University, 744 Motooka, Nishi, Fukuoka, Fukuoka 819–0395, Japan
6 Research Center of Advanced Particle Physics, Kyushu University, 744 Motooka, Nishi, Fukuoka, Fukuoka 819–0395, Japan
7 Institute of Material Structure Science, High Energy Accelerator Organization (KEK), Oho 1–1, Tsukuba, Ibaraki 305–0801, Japan
8 Department of Physics, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro, Tokyo 152–8551, Japan
9 Department of Chemistry, UBC Faculty of Science, University of British Columbia, Vancouver, British Columbia V6R1Z1, Canada
10 Department of Earth and Environmental Sciences, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990–8560, Japan
11 Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Japan
12 Research Reactor Institute, Kyoto University, 2 Asashiro-nishi, Kumatoricho, Senngan-gun, Osaka 590–0494, Japan
13 Research Center for Nuclear Physics, Osaka University, 10–1 Mihogaoka, ibaraki, Osaka 567–0047, Japan
14 RIKEN Center for Advanced Photonics, RIKEN, Hirosawa 2–1, Wako, Saitama 351–0198, Japan
a e-mail: email@example.com
Published online: 12 December 2019
Parity violating effects enhanced by up to 106 times compared to proton-proton scattering have been observed in several neutron capture induced compound nuclei. This enhancement is explained as an interference between an s-wave and a p-wave amplitude (s-p mixing). Theory predicts that this mechanism can also enhance T-violating effects. For estimation of this enhancement in a promising candidate nucleus, we measured the angular distribution of γ-rays in the (n,γ) reaction induced in a 139La target. Experiments were performed at J-PARC, using a germanium detector array at an intense neutron beam. Analysis of the observed angular dependence around the 0.74 eV p-wave resonance allowed us to determine the ratio of the partial p-wave neutron width to the total neutron width in the entrance channel of the compound nucleus. We also report our development of a 3He spin filter needed as an epithermal-neutron polarizer for the T-violation search.
© The Authors, published by EDP Sciences, 2019
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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