  Self-consistent Ansaetze are presented for the left- and right-handed
isodoublet fermion zero-modes of the constrained instanton Istar in the vacuum
sector of euclidean SU(2) Yang-Mills-Higgs theory. These left- and right-handed
fermion wave functions do not coincide and, most likely, have maxima at
different positions. This may be important for the fermion zero-mode
contribution to the euclidean 4-point Green's function in chiral
Yang-Mills-Higgs theory and the high-energy behaviour of fermion-fermion
scattering processes.
