Improved measurements of neutron lifetime with cold neutron beam at J-PARC

• DOI: 10.48550/arxiv.2412.19519
• Publication Date: 2024-12-27
• Authors: Y. Fuwa; T. Hasegawa; K. Hirota; T. Hoshino; R. Hosokawa; Go Ichikawa; S. Ieki; T. Ino; Yoshihisa Iwashita; Masaaki Kitaguchi; Ryunosuke Kitahara; S. Makise; K. Mishima; Tatsushi Mogi; Naoki Nagakura; H. Oide; H. Okabe; Hidetoshi Otono; Yoshichika Seki; Daiichiro Sekiba; T. Shima; Hirohisa SHIMIZU; H. M. Shimizu; N. Sumi; Hirochika Sumino; M. Tanida; Hokuto Uehara; T. Yamada; S. Yamashita; Kazumi Yano; T. Yoshioka
• Keywords: J-PARC; Neutron radiation

The ``neutron lifetime puzzle'' arises from the discrepancy between neutron measurements obtained using beam method, which measures decay products, and bottle disappearance of neutrons. To resolve this puzzle, we conducted an experiment a pulsed cold at J-PARC. In experiment, is determined ratio counts to $^3$He(n,p)$^3$H reactions in gas detector. This belongs method but differs previous experiments that measured protons, as it instead detects electrons, enabling with distinct systematic uncertainties. By enlarging transport system reducing uncertainties, achieved fivefold improvement precision. Analysis all acquired data yielded $\tau_{\rm n}=877.2~\pm~1.7_{\rm(stat.)}~^{+4.0}_{-3.6}{}_{\rm (sys.)}$ s. result consistent exhibits 2.3$\sigma$ tension average value proton-detection-based method.