The hypercentral Constituent Quark Model

We report on the results of a Constituent Quark Model based oil a hypercentral approach (hCQM), including three-body force and standard two-body potential contributions. The model contains a hypercentral interaction, to which a hyperfine, SU(6)-breaking term, is added. The model (the only three parameters being fixed to the spectrum) has been used for the calculation of the electromagnetic transition amplitudes for all the 3- and 4-star resonances below 2 GeV and the e.m. elastic form factors. The effect of introducing relativistic corrections (boosts) is also considered. The results are compared to the experimental data, with particular attention to the ratio mu(p) G(E)/G(M) recently measured at TJNAF. The hypercentral potential supplies a realistic set of quark wave functions, as shown by the results obtained with this model for the electromagnetic transition form factors, in particular for the S-11(1535) resonance. Finally we discuss a generalization of the SU(6)-breaking term and thanks to the isospin dependence, the model gives a description of the baryon spectrum which is very good also in its fine details up to 2 GeV, even for the Roper resonance position.