Hans Koch, Charles Radin, Lorenzo Sadun
Most stable structure for hard spheres
(262K, postscript)

ABSTRACT.  The hard sphere model is known to show a liquid-solid phase 
transition, with the solid expected to be either face centered cubic 
or hexagonal close packed. The differences in free energy of the two 
structures is very small and various attempts have been made to 
determine which structure is the more stable. We contrast the 
different approaches and extend one.