Meson-Exchange Currents in Quasielastic Charged-Current Neutrino Reactions with Single-Nucleon Knockout

TL;DR

This paper investigates how meson-exchange currents affect quasielastic charged-current neutrino scattering, showing they reduce response functions and cross sections, with comparisons across different nuclear models.

Contribution

It provides a relativistic calculation of meson-exchange current effects on neutrino scattering, including comparisons with non-relativistic and other relativistic models.

Findings

Reduction in vector, axial, and vector-axial response functions.

Decrease in total neutrino cross section due to meson-exchange currents.

Qualitative agreement across different nuclear models.

Abstract

The effect of meson-exchange currents on charged-current quasielastic neutrino scattering with single-nucleon emission is computed and analyzed within the relativistic Fermi gas model. This contribution arises primarily from the interference between one-body and two-body currents, where the two-body operator excites a 1p1h state in the presence of a second, spectator nucleon. The results obtained show a reduction of the vector, axial and vector-axial transverse response functions and, consequently, a decrease in the total neutrino cross section. In addition to a comparison with the non-relativistic limit, other models are also explored, such as the relativistic mean field model for nuclear matter and the superscaling analysis with relativistic effective mass, both of which yield qualitatively similar results.