Extended superscaling with two-particle emission in electron and neutrino scattering

Abstract

An extended superscaling analysis of quasielastic electron-scattering data is proposed by parametrizing the scaling function as the sum of a symmetric function corresponding to the emission of a single particle plus a contribution from the phase space of two-particle emission. The phase space of two-particle emission (2p2h) is multiplied by a q-dependent parameter that has been fitted to describe the tail behavior of the scaling function. This approach allows for an alternative description of the quasielastic electron scattering data, incorporating the contributions from both single-particle and two-particle emission processes induced by the one-body current and explaining the asymmetry of the scaling function. In a factorized schematic model based on the independent-pair approximation, the 2p2h parameter is related to the high-momentum distribution of the pair averaged over 2p2h excitations. However, in the phenomenological fitting approach undertaken here, this coefficient includes other contributions such as interference with two-body currents and effects of the final-state interactions. We present predictions for the inclusive two-nucleon emission cross section induced by electrons and neutrinos.

Meson-Exchange Currents in Quasielastic Electron Scattering in a Generalized Superscaling Approach

“…This is in agreement with the conclusion of Fabrocini, as the tensor-isospin term precisely generates this significant difference between PP and PN pairs. An alternative way to investigate this hypothesis would be to perform calculations in the independent particle model by solving the Bethe-Goldstone equation [91] for PP and PN pairs and using a correlation current similar to the one proposed in [92]. Such calculations could provide further insights into the effect of short-range correlations on the MEC contributions to the transverse response.…”