Lifetime of the hypertriton

0568498 - ÚJF 2023 RIV FR eng C - Conference Paper (international conference)
Gazda, Daniel - Pérez-Obiol, A. - Gal, A. - Friedman, E.
Lifetime of the hypertriton.
EPJ Web of Conferences. Vol. 271. Les Ulis: EDP Science, 2022, č. článku 01002. E-ISSN 2100-014X.
[14th International Conference on Hypernuclear and Strange Particle Physics (HYP2022). Prague (CZ), 27.06.2022-01.07.2022]
R&D Projects: GA ČR GA19-19640S; GA ČR(CZ) GA22-14497S
Research Infrastructure: e-INFRA CZ - 90140
Institutional support: RVO:61389005
Keywords : relativistic heavy ion collision * hypertrion lifetime
OECD category: Nuclear physics
https://doi.org/10.1051/epjconf/202227101002

Conflicting values of the hypertriton lifetime τ(3ΛH) were derived in relativistic heavy ion (RHI) collision experiments over the last decade. A very recent ALICE Collaboration measurement is the only experiment where the reported τ(3ΛH) comes sufficiently close to the free-Λ lifetime τΛ, as expected naively for a very weakly bound Λ in 3ΛH. We revisited theoretically this 3ΛH lifetime puzzle [1], using 3ΛH and 3He wave functions computed within the ab initio no-core shell model employing interactions derived from chiral effective field theory to calculate the two-body decay rate Γ(3ΛH → 3He + π−). We found significant but opposing contributions arising from ΣNN admixtures in 3ΛH and from π− − 3He final-state interaction. To derive τ(3ΛH), we evaluated the inclusive π− decay rate Γπ− (3ΛH) by using the measured branching ratio Γ(3ΛH → 3He + π−)/Γπ− (3ΛH) and added the π0 contributions through the ΔI = 1/2rule. The resulting τ(3ΛH) varies strongly with the rather poorly known Λ separation energy Esep(3ΛH) and it is thus possible to associate each one of the distinct RHI τ(3ΛH) measurements with its own underlying value of Esep(3ΛH).
Permanent Link: https://hdl.handle.net/11104/0339799