Consequences of increased hypertriton binding for s -shell Λ -hypernuclear systems

Consequences of increasing the binding energy of the hypertriton ground state HΛ3(JP=12+) from the emulsion value BΛEMUL(Hg.s.Λ3)=0.13±0.05 MeV to the STAR value BΛSTAR(Λ3H)=(0.41±0.12±0.11) MeV are studied for s-shell hypernuclei within a pionless effective field theory (π EFT) approach at leading order, constrained by the binding energies of the 0+ and 1+HΛ4 states. The stochastic variational method is used in bound-state calculations, whereas the inverse analytic continuation in the coupling constant method is used to locate S-matrix poles of continuum states. It is found that the Λnn(12+) resonance becomes broader and less likely to be observed experimentally, whereas the HΛ3(32+) spin-flip virtual state moves closer to the Λd threshold to become a shallow bound state for specific ΛN interaction strengths. The effect of such a near-threshold HΛ3(32+) state on femtoscopic studies of Λ-deuteron correlations, and its lifetime if bound, are discussed. Increasing BΛ(Hg.s.Λ3) moderately, up to ≈0.5 MeV, hardly affects calculated values of BΛ(HeΛ5).