Electron- and neutrino-nucleus scattering in the impulse approximation regime

Abstract

A quantitative understanding of the weak nuclear response is a prerequisite for the analyses of neutrino experiments such as K2K and MiniBOONE, which measure energy and angle of the muons produced in neutrino-nucleus interactions in the energy range 0:5-3 GeV and reconstruct the incident neutrino energy to determine neutrino oscillations. In this paper we discuss theoretical calculations of electron-and neutrino-nucleus scattering, carried out within the impulse approximation scheme using realistic nuclear spectral functions. Comparison between electron scattering data and the calculated inclusive cross section of oxygen, at beam energies ranging between 700 and 1200 MeV, show that the Fermi gas model, widely used in the analysis of neutrino oscillation experiments, fails to provide a satisfactory description of the measured cross sections, and inclusion of nuclear dynamics is needed.

Construction of spectral functions for medium-mass nuclei

“…II with the existing electron scattering data. Since description of the dip region and the ∆ excitation is ambiguous [5,42,43], our considerations include QE interactions only and we test predictions of the obtained SFs in energy transfers below the QE peak. Figures 5-7 show comparison with a wide spectrum of experimental points.…”

“…The basic assumption underlying the presented approach is the IA, therefore the MF part of the SF can be written in the form (compare [5,24,25]):…”

“…Detailed verification of the description is performed using two targets, namely oxygen and calcium. Oxygen was selected because of additional opportunity to compare results with a more systematic theoretical approach to modeling of the SF [5], whereas the calcium nucleus is most similar to argon's, for which precise measurements have been performed. Our description of 40 20 Ca is confronted also with the theoretical results of Butkevich and Mikheyev [6].…”

Measurement of the neutrino-oxygen neutral-current interaction cross section by observing nuclear deexcitationγrays

“…Approximately 20% of the total spectral strength is pushed by N N correlations out of the Fermi sea into continuum states [34]. The electron scattering results are incorporated into a realistic spectral function model in [29], which was integrated in momentum and energy in [8] to calculate the spectroscopic factors for the shell states shown in table I. Since the 1p 1/2 hole is already the ground state, it produces no primary γ-rays.…”

“…The NCQE cross section on oxygen is simulated using a spectral function model [29,30] with the BBBA05 form factor parameterization [31], which is then reweighted as a function of neutrino energy to match the recent theoretical calculations from [8]. In order to simulate the [8], while the branching ratios were measured with electron and proton scattering [24][25][26].…”