Four-Body Scale in Universal Few-Boson Systems

Understand

The role of an intrinsic four-body scale in universal few-boson systems is the subject of active debate.

• We study these systems within the framework of effective field theory.
• For systems of up to six bosons we establish that no four-body scale appears at leading order (LO).
• However, we find that at next-to-leading (NLO) order a four-body force is needed to obtain renormalized results for binding energies.