Hi there, I've been trying to understand the theory to descibe the delta(1232) resonance but I'm stuck... hope you guys could help me. After reading several papers, the following questions arose: 1. How do I get (mathematically) the spinor respresentation (1/2,0)+(1,1/2)+(0,1/2)+(1/2,1) from the product of a vector and a spin-1/2 spinor? Why don't we use the (3/2, 0)-representation (I think this was alreay asked)? 2. Problem with the lower spin components (s-1), (s-2), etc. corresponding to the (1/2,0)+(0,1/2) in the upper representation: How do I "see" them in the RS-Lagrangian? Is this problem exisiting in a Spin-1-theory: do Spin-0 d.o.f.s arise there? 3. We remove the Spin 1/2 contributions by the constrain: γμψμ=0, where γ are the gamma matrices and ψ is the RS-field. What does this mean? 4. Why the consistent(physical) vertex has to satisfy pμ[itex]\Gamma[/itex][itex]\mu[/itex]=0, with pμ being the 4-momentum? These questions remain unanswered to me. Thanks for reply!