Improvement of systematic uncertainties for the neutron lifetime experiment at J-PARC

T. Mogi, T. Hasegawa, K. Hirota, G. Ichikawa, S. Ieki, T. Ino, Y. Iwashita, S. Kajiwara, Y. Kato, M. Kitaguchi, R. Kitahara, J. Koga, S. Makise, S. Matsuzaki, K. Mishima, K. Morikawa, N. Nagakura, H. Okabe, H. Otono, Y. SekiD. Sekiba, T. Shima, H. E. Shimizu, H. M. Shimizu, Y. Sugisawa, N. Sumi, H. Sumino, T. Tanabe, T. Tomita, H. Uehara, T. Yamada, S. Yamashita, K. Yano, T. Yoshioka

Research output: Contribution to journalConference articlepeer-review


The neutron lifetime is one of the important parameters for particle physics and astrophysics. There is a 4.6σ (9.5 s) discrepancy between the results of the two typical methods. To solve this discrepancy, a new neutron lifetime experiment with a different method is in progress at J-PARC, and this experiment published the first result in 2020 of 898 ± 10(stat.) + 15/−18(syst.) s. We have performed improvements to reduce systematic uncertainties towards 1 s accuracy. The methods to measure the amount of 3He injected and in the working gas have been upgraded, and a new model for the space charge effect in the Monte Carlo simulation has been implemented.

Original languageEnglish
Article number458
JournalProceedings of Science
Publication statusPublished - May 24 2022
Event22nd Particles and Nuclei International Conference, PANIC 2021 - Virtual, Online, Portugal
Duration: Sept 5 2021Sept 10 2021

All Science Journal Classification (ASJC) codes

  • General


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