Superscaling analysis of quasielastic electron scattering with relativistic effective mass

Abstract

We provide a parametrization of a new phenomenological scaling function obtained from a chisquare fit to a selected set of (e,e') cross section data expanding a band centered around the quasielastic peak. We start from a re-analysis of quasielastic electron scattering from nuclear matter within the relativistic mean field model. The cross section depends on the relativistic effective mass of the nucleon, m * N , and it scales with respect to a new scaling variable, ψ * . This suggests a new superscaling approach with effective mass (SuSAM*) for predicting quasielastic cross sections within an uncertainty band. The model reproduces previously established results on the enhancement of the transverse response function as compared to the traditional relativistic Fermi gas.

Meson-exchange currents and superscaling analysis with relativistic effective mass of quasielastic electron scattering from C12

“…We carried out such analyses in Refs. [43][44][45][46]. In the SuSAM* models, the response functions are computed by using Eq.…”

“…4, we plot f * versus ψ * for all the data of 12 C. The values of M * = 0.8 and Fermi momentum k F = 225 MeV/c have been taken from the previous analyses of Refs. [43][44][45][46], where it was shown that these values provide the best scaling of data. In Fig.…”

“…To discard the data, we apply a density criterion by computing the density of the points in the plot and keeping only those points surrounded by more than 25 points within a circle of radius r = 0.1. This is the same criterion used in our previous works [43][44][45][46].…”

“…The goal of this work is to present a model that shares and unifies the ideas of the RMF, superscaling, and MEC in a consistent way. The idea is to extend our previous works on superscaling with relativistic effective mass [43][44][45][46] to include the 2p-2h contribution, taking into account the interactions of nucleons with the relativistic mean field. The attractive scalar potential is accounted for in the relativistic effective mass m * N < m N , while the vector potential produces a repulsive energy that has an important effect in the MEC.…”

“…In the original SuSAM* studies [43][44][45][46], a new superscaling function f * (ψ * ) was obtained from the electron scattering cross-section data, by using the scaling variable ψ * of the RMF. The model can describe a large amount of the quasielastic electron data for many nuclei within a theoretical error band.…”