Precise lifetime measurement of ⁴H hypernucleus using in-flight 4He( K-, 0)⁴H reaction

We present a new measurement of the H-4(Lambda) hypernuclear lifetime using in-flight K- + He-4 -> H-4(Lambda) + pi(0) reaction at the J-PARC hadron facility. We demonstrate, for the first time, the effective selection of the hypernuclear bound state using only the gamma-ray energy decayed from pi(0). This opens the possibility for a systematic study of isospin partner hypernuclei through comparison with data from (K-, pi(-)) reaction. As the first application of this method, our result for the H-4(Lambda) lifetime, tau(H-4(Lambda)) = 206 +/- 8(stat.) +/- 12(syst.) ps, is one of the most precise measurements to date. We are also preparing to measure the lifetime of the hypertriton (H-3(Lambda)) using the same setup in the near future. (C) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).