Covariant model for the Dalitz decay of the $N(1535)$ resonance

We develop a covariant model for the gamma*N -> N(1535) transition in the timelike kinematical region, the region where the square momentum transfer q(2) is positive. Our starting point is the covariant spectator quark model constrained by data in the spacelike kinematical region (Q(2) = -q(2) >= 0). The model is used to estimate the contributions of valence quarks to the transition form factors, and one obtains a fair description of the Dirac form factor at intermediate and large Q(2). For the Pauli form factor there is evidence that beyond the quark-core contributions there arc also significant contributions of meson cloud effects. Combining the quark-core model with an effective description of the meson cloud effects, we derive a parametrization of the spacelike data that can be extended covariantly to the timelike region. This extension enabled us to estimate the Dalitz decay widths of the N(1535) resonance, among other observables. Our calculations can help in the interpretation of the present experiments at HADES (pp collisions and others).