Nucleon in the chiral quark model: An alternative computation scheme

We formulate the quark sea contributions to the energy and various physical observables in terms of Euclidean Green functions and their K-spin partial wave reduction. In this framework it is not necessary to discretize the continuous spectrum by introducing a finite boundary. Using this formulation we perform a new self-consistent computation of the nucleon state in the Nambu–Jona-Lasinio model. In addition to this technical advantage, such an alternative computation scheme makes it possible to obtain the numerical predictions of the model in an entirely independent way. We use the Pauli-Villars cutoff to define the model. Our results for the nucleon energy, the mesonic profile, and various observables essentially confirm results obtained by other groups using this regularization. The results for g_A, obtained on the basis of quark currents, are close to the experimental value.