The $B=5$ Skyrmion as a two-cluster system

Abstract: The classical $B=5$ Skyrmion can be approximated by a two-cluster system where a $B=1$ Skyrmion is attached to a core $B=4$ Skyrmion. We quantise this system, allowing the $B=1$ to freely orbit the core. The configuration space is 11-dimensional but simplifies significantly after factoring out the overall spin and isospin degrees of freedom. We exactly solve the free quantum problem and then include an interaction potential between the Skyrmions numerically. The resulting energy spectrum is compared to the corresponding nuclei -- the Helium-5/Lithium-5 isodoublet. We find approximate parity doubling not seen in the experimental data. In addition, we fail to obtain the correct ground state spin. The framework laid out for this two-cluster system can readily be modified for other clusters and in particular for other $B=4n+1$ nuclei, of which the $B=5$ is the simplest example.