Fission and Fusion Bound States of p-brane Solitons
  Supersymmetric $p$-branes that carry a single electric or magnetic charge and preserve $1/2$ of the supersymmetry have been interpreted as the constituents from which all supersymmetric $p$-branes can be constructed as bound states, albeit with zero binding energy. Here we extend the discussion to non-supersymmetric $p$-branes, and argue that they also can be interpreted as bound states of the same basic supersymmetric constituents. In general, the binding energy is non-zero, and can be either positive or negative depending on the specific choice of constituents. In particular, we find that the $a=0$ Reissner-Nordstr\o{m} black hole in $D=4$ can be built from different sets of constituents such that it has zero, positive or negative binding energy. 
H. Lu and C.N. Pope