Mass terms in the Skyrme Model
  We consider various forms of the mass term that can be used in the Skyrme model and their implications on the properties of baryonic states. We show that, with an appropriate choice for the mass term, without changing the asymptotic behaviour of the profile functions at large $r$, we can considerably reduce or increase the mass term's contribution to the classical mass of the solitons. We find that multibaryon configurations can be classically bound at large baryon numbers for some choices of this mass term. 
V.B. Kopeliovich, B. Piette and W.J. Zakrzewski