Big Bang Nucleosynthesis: The Strong Nuclear Force meets the Weak
  Anthropic Principle
  Contrary to a common argument that a small increase in the strength of the
strong force would lead to destruction of all hydrogen in the big bang due to
binding of the diproton and the dineutron with a catastrophic impact on life as
we know it, we show that provided the increase in strong force coupling
constant is less than about 50% substantial amounts of hydrogen remain. The
reason is that an increase in strong force strength leads to tighter binding of
the deuteron, permitting nucleosynthesis to occur earlier in the big bang at
higher temperature than in the standard big bang. Photodestruction of the less
tightly bound diproton and dineutron delays their production to after the bulk
of nucleosynthesis is complete. The decay of the diproton can, however, lead to
relatively large abundances of deuterium.
