Electromagnetic nucleon properties and quark sea polarization in the Nambu-Jona-Lasinio model

In this paper we present the derivation as well as the numerical results for all electromagnetic form factors of the nucleon within the semibosonized Nambu--Jona-Lasinio (chiral quark soliton) model. Other observables, namely the nucleon mean squared radii, the magnetic moments and the nucleon--$\Delta$ splitting are also computed. The calculation has been done taking into account the quark sea polarization effects. The final results, including rotational $1/N_c$ corrections, are compared with the existent experimental data and they are found to be in a good agreement for the constituent quark mass of $400$--$420\ MeV$.