The spin jumping in the context of a QCD effective model

The tensor formulation for the effective theory of QCD vector ressonances, whose model we denote by TEVR, is given by an antisymmetric tensor field and describes spin 1 particles. Our goal is to show, by diferent approaches, that the Abelian version of this model presents the so called "spin jumping" when we consider its massless limit. Classically we find, by the use of the equations of motion and the Hamiltonian constraint analysis, that the massive phase of the model describes spin 1 particles while its massless phase describes spin 0 particles. By the quantum point of view we derive these conclusions via tree level unitarity analysis and the master action approach.