Towards resolving the 3ΛH lifetime puzzle

Recent H-3(Lambda) lifetime measurements in relativistic heavy ion collision experiments have yielded values shorter by (30 +/- 8)% than the free Lambda lifetime tau(Lambda), thereby questioning the naive expectation tau(H-3(Lambda)) approximate to tau(Lambda) for a weakly bound Lambda hyperon. Here we apply the closure approximation introduced by Dalitz and coworkers to evaluate the H-3(Lambda) lifetime, using H-3(Lambda) wavefunctions generated by solving three-body Faddeev equations. Our result, disregarding pion final-state interaction (FSI), is tau(H-3(Lambda))=(0.90 +/- 0.01)tau(Lambda). In contrast to previous works, pion FSI is found attractive, reducing further tau(H-3(Lambda)) to tau(H-3(Lambda))=( 0.81 +/- 0.02)tau(Lambda). We also evaluate for the first time tau((3)(Lambda)n), finding it considerably longer than tau(Lambda), contrary to the shorter lifetime values suggested by the GSI HypHI experiment for this controversial hypernucleus. (c) 2019 The Author(s). Published by Elsevier B.V.