Measurement of P-Violation in ¹³⁹La(n,γ)¹⁴⁰La – a first step towards a T-Violation search

¹ Department of Physics, Nagoya University, Furocho, Chikusa, Nagoya, Aichi 464–8601, Japan
² Kobayashi-Maskawa Institute, Nagoya University, Furocho, Chikusa, Nagoya, Aichi 464–8601, Japan
³ Department of Physics, Kyushu University, 744 Motooka, Nishi, Fukuoka, Fukuoka 819–0395, Japan
⁴ Research Center of Advanced Particle Physics, Kyushu University, 744 Motooka, Nishi, Fukuoka, Fukuoka 819–0395, Japan
⁵ Institute of Material Structure Science, High Energy Accelerator Organization (KEK), Oho 1–1, Tsukuba, Ibaraki 305–0801, Japan
⁶ Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152–8551, Japan
⁷ University of British Columbia, Vancouver, British Columbia V6R1Z1, Canada
⁸ Yamagata University, 1-41-2 Koshirakawa, Yamagata 990–8560, Japan
⁹ Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Japan
¹⁰ Research Reactor Institute, Kyoto University, Kumatori, Osaka 590–0494, Japan
¹¹ Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047, Japan
¹² RIKEN, 2–1 Hirosawa, Wako, Saitama 351–0198, Japan

Published online: 13 December 2019

Abstract

We performed a polarized neutron transmission asymmetry measurement utilizing the ¹³⁹La(n,γ)¹⁴⁰La reaction. This measurement involved the use of a recently developed ³He spin filter mounted on the J-PARC MLF beam line number 4 (BL04). The resulting value of the longitudinal asymmetry A_L = (11.7 ± 1.1)% was found to be in good agreement with existing values in the literature suggesting that the method by which we polarize the neutron beam is not a significant source of uncertainty. This preliminary work represents a first step toward future measurements of the angular correlation in (n̅,Υ) reactions necessary in the search for enhanced T-Violation in compound nuclei.