A three-body force model for the electromagnetic excitation of the nucleon

We have performed a calculation of the helicity amplitudes for the electromagnetic excitation of nucleon resonances based on a three-body force model for baryon structure. All parameters have been previously fixed studying the baryon spectrum and therefore this is a parameter free calculation. We have taken into account the hyperfine mixing in all the baryon states and we present our results in comparison with those given by other approaches proposed in the literature. A brief discussion on open problems is also given.