  Extremely weakly-bound three-boson systems are predicted to exhibit
intriguing universal properties such as discrete scale invariance. Motivated by
recent experimental studies of the ground and excited helium trimers, this work
analyzes the three-body parameter and the structural properties of three helium
atoms as the s-wave scattering length is tuned artificially. Connections with
theoretical and experimental studies of the Efimov scenario as it pertains to
cold atom systems are made.
