ΛΛ4H in halo effective field theory

The H-4(Lambda Lambda) bound state and the S-wave hypertriton(H-3(Lambda))-Lambda scattering in spin singlet and triplet channels below the hypertriton breakup momentum scale are studied in halo/cluster effective field theory at leading order by treating the H-4(Lambda Lambda) system as a three-cluster (Lambda-Lambda-deuteron) system. In the spin singlet channel, the amplitude is insensitive to the cutoff parameter Lambda(c) introduced in the integral equation, and we find that there is no bound state. In this case, the scattering length of the hypertriton-Lambda scattering is found to be a(0) = 16.0 +/- 3.0 fm. In the spin triplet channel, however, the amplitude obtained by the coupled integral equations is sensitive to Lambda(c), and we introduce the three-body contact interaction g(1) (Lambda(c)). After phenomenologically fixing g(1) (Lambda(c)), we find that the correlation between the two-Lambda separation energy B-Lambda Lambda from the H-4(Lambda Lambda) bound state and the scattering length a(Lambda Lambda) of the S-wave Lambda-Lambda scattering is significantly sensitive to the value of Lambda(c).