Relativistic Covariance of Light-Front Few-Body Systems in Hadron   Physics
  We study the light-front covariance of a vector-meson decay constant using a manifestly covariant fermion field theory model in $(3+1)$ dimensions. The light-front zero-mode issues are analyzed in terms of polarization vectors and method of identifying the zero-mode operator and of obtaining the light-front covariant decay constant is discussed. 
Ho-Meoyng Choi (KNU) and Chueng-Ryong Ji (NCSU)
hep-ph