90 -
J.P.B.C. de Melo (Laboratorio de Fisica Teorica e Computac{c}~aon Cientifica
, LFTC
, Universidade Cruzeiro do Sul
2012
The contribution of the light-front valence wave function to the electromagnetic current of spin-1 composite particles is not enough to warranty the proper transformation of the current under rotations. The naive derivation of the plus component of t
he current in the Drell-Yan-West frame within an analytical and covariant model of the vertex leads to the violation of the rotational symmetry. Computing the form-factors in a quasi Drell-Yan-West frame $q^+rightarrow 0$, we were able to separate out in an analytical form the contributions from Z-diagrams or zero modes using the instant-form cartesian polarization basis.