Natural Higgs-flavor-democracy solution of the mu problem of
  supersymmetry and the QCD axion
  We show that the hierarchically small mu term in supersymmetric theories is a
consequence of two identical pairs of Higgs doublets taking a democratic form
for their mass matrix. We briefly discuss the discrete symmetry S2xS2 toward
the democratic mass matrix. Then, we show that there results an approximate
Peccei-Quinn symmetry and hence the value mu is related to the axion decay
constant.
