Pairs in the light-front and covariance

Abstract

The electromagnetic current of bound systems in the light-front is constructed in the Breit-Frame, in the limit of momentum transfer $q^{+}=(q^0+q^3)$ vanishing. In this limit, the pair creation term survives and it is responsible for the covariance of the current. The pair creation term is computed for the $j^{+}$ current of a spin one composite particle in the Breit-frame. The rotational symmetry of $j^{+}$ is violated if the pair term is not considered.

Comments: 8 pages latex,revtex. e-mail: pacheco@axpfep1.if.usp.br and tobias@fis.ita.cta.br