Analytic parametrizations of the γ~*N → N(1440) form factors inspired by light-front holography

摘要

We present analytic parametrizations for the γ~*N → N(1440) form factors derived from light-front holography in leading twist approximation. The new parametrizations describe the electromagnetic form factors using analytic functions dependent on the masses of the ρ meson and respective radial excitations, as well as the masses of the nucleon and the resonance N(1440). The free parameters of the model, associated with three independent couplings, are interpreted as bare couplings, and are fixed by the nucleon data for large Q~2. The proposed parametrizations compare remarkably well with the empirical data for Q~2 > 2 GeV~2, corroborating the dominant role of the valence quark degrees of freedom in the γ~*N → N(1440) transition.