We investigate the dispersion relation of Mobius domain-wall fermions in free field theory at finite $L_s$. We find that the quark propagator constructed from the domain-wall fermion operator has $L_s-1$ extra poles as well as the pole which realizes the physical quark in the continuum limit. The unphysical contribution of these extra poles could be significant when we introduce heavy quarks. In this talk, we will show the basic properties of these unphysical poles and discuss the optimal choice of Mobius parameters to minimize their contribution to the 4D physics.

Weak Decays and Matrix Elements