Hyperfine structure splitting of the bound $S(L = 0)-$states in the   symmetric muonic molecular ions
  The hyperfine structure splittings are determined for all five bound $S(L = 0)-$states in the three symmetric muonic molecular ions: $pp\mu, dd\mu$ and $tt\mu$. The expectation values of all interparticle delta-functions used in our calculations have been determined in recent highly accurate computations. 
Alexei M. Frolov
physics.atom-ph nucl-th