The longitudinal and transverse responses in the inclusive electron scattering

The splitting between the charge-longitudinal and spin-transverse responses is explained in a model whose inputs are the effective interactions in the particle-hole channels in the first order boson loop expansion. The interplay between $\omega$-meson exchange and box diagrams mainly governs the longitudinal response, while in the transverse one the direct $\Delta$ excitations almost cancel the one-loop correction and the response is ruled by the $\rho$-meson rescattering.