Inclusive electron scattering within the SuSAv2 meson-exchange current approach

Abstract

We present our recent progress on the relativistic modeling of electron-nucleus reactions and compare our predictions with inclusive 12 C (e, e ′ ) experimental data in a wide kinematical region. The model, originally based on the superscaling phenomenon shown by electron-nucleus scattering data, has recently been improved through the inclusion of Relativistic Mean Field theory effects that take into account the enhancement of the quasielastic transverse scaling function compared with its longitudinal counterpart. In this work we extend the model to include the complete inelastic spectrum -resonant, non-resonant and deep inelastic scattering (DIS). We also discuss the impact of meson-exchange currents (MEC) through the analysis of two-particle two-hole contributions to electromagnetic response functions evaluated within the framework of the relativistic Fermi gas, considering for the first time not only the transverse but also the longitudinal channel. The results show quite good agreement with data over the whole range of energy transfer, including the dip region between the quasielastic peak and the ∆ resonance.

Charged-current neutrino-nucleus reactions within the superscaling meson-exchange current approach

“…As anticipated in the Introduction, in this work we evaluate the nuclear responses by employing a set of purely isovector scaling functions based on the RMF and the RPWIA models (SuSAv2 model) in order to account properly the FSI between the outgoing nucleon and the residual nucleus, as described in [14,23]. Contrary to the original SuSA approach that makes use of a singleuniversal scaling function extracted from the analysis of the longitudinal response function for electron scattering, the new SuSAv2 incorporates more degrees of freedom by employing also an enhanced transverse scaling function that is consistent with the theoretical predictions provided by the RMF.…”

“…This has been recently studied in detail in [14], where good agreement with (e, e ′ ) data is reached in the framework of the SuperScaling Approach (SuSA) for a wide range of kinematics, covering from the QE regime to the deep inelastic spectrum.…”

“…The pure RMF model fails to reproduce the smooth transition to the RPWIA at high q due to the strong energyindependent scalar and vector potentials included in the model. Hence both approaches are incorporated in the present SuSAv2 model by using a q-dependent blending function, as described in [14], in such a way that the RMF dominates at low and intermediate q-values whereas the RPWIA contributions start to be relevant at higher momentum transfer. The same approach has been applied not only to the QE but also to the inelastic regime and has been shown to provide a successful description of electron-nucleus inclusive data [14] once 2p-2h excitations are also taken into account.…”

Density dependence of 2p-2h meson-exchange currents

“…Whereas most of the existing calculations refer to a 12 C target [13,15,[26][27][28][29][30][31][32][33], there is growing interest in the extension to heavier nuclei, such as 16 O, 40 Ar, 56 Fe, and 208 Pb, used in ongoing and future neutrino experiments. Since the calculation of the 2p-2h response is computationally demanding and time consuming, in this paper we provide an estimate of the density dependence of these contributions which can be used to extrapolate the results from one nucleus to another.…”

Meson-exchange currents and quasielastic predictions for neutrino-nucleus scattering

“…The SuSAv2 predictions for inclusive (e, e ′ ) scattering on 12 C have been presented in [3], where they are shown to provide a remarkably good description of the data for very different kinematical situations. In order to perform such comparison the SuSAv2 model has been extended from the the quasielastic (QE) domain to the inelastic region by employing phenomenological fits to the single-nucleon inelastic electromagnetic structure functions.…”