  In the domain wall fermion formulation, chiral symmetry breaking in full QCD
is expected to fall exponentially with the length of the extra dimension. We
measure the chiral symmetry breaking due to a finite extra dimension in two
ways, which can be affected differently by finite volume and explicit fermion
mass. For quenched QCD the two methods generally agree, except for the largest
extent of the extra dimension, which makes the limit uncertain. We have less
data for full QCD, but see exponential suppression for the method where we have
data.
