Quasielastic axial-vector mass from experiments on neutrino–nucleus scattering

Abstract

Abstract. We analyse available experimental data on the total and differential charged-current cross sections for quasielastic νµN and νµN scattering, obtained with a variety of nuclear targets in the accelerator experiments at ANL, BNL, FNAL, CERN, and IHEP, dating from the end of sixties to the present day. The data are used to adjust the poorly known value of the axial-vector mass of the nucleon.

Measurement of Muon Antineutrino Quasielastic Scattering on a Hydrocarbon Target atEν∼3.5 GeV

“…Vector form factors come from fits to Backgrounds from baryon resonance production (light grey), continuum/deep-inelastic scattering (dark grey), and other sources (black),such as coherent pion production, are shown. The fraction of signal in this sample, before requiring low recoil energy, is 0.58. electron scattering data [32]; the axial form factor used is a dipole with an axial mass (M A ) of 0.99 GeV/c 2 , consistent with deuterium measurements [8,9]; and subleading form factors are assumed from PCAC or exact G-parity symmetry [33]. The nuclear model is the relativistic Fermi gas (RFG) with a Fermi momentum of 221 MeV/c and an extension to higher nucleon momenta to account for short-range correlations [34,35].…”

“…Quasi-elastic interactions, νp → + n and νn → − p, have simple kinematics and serve as reference processes in those experiments [1,6,7] at GeV energies. These processes are typically modeled as scattering on free nucleons in a relativistic Fermi gas (RFG), with a nucleon axial form factor measured in neutrino-deuterium quasi-elastic scattering [8,9]. In the RFG model [10] the initial state nucleons are independent in the mean field of the nucleus, and therefore the neutrino energy and momentum transfer Q 2 can be estimated from the polar angle θ and momentum p of the final state lepton.…”

Neural network parameterizations of electromagnetic nucleon form-factors

“…(1.5) M A denotes the axial mass. Notice that recent studies [19,20] suggest M A value larger by about 20% with respect to the old measurements [21][22][23]. The impact of the electromagnetic form-factors on the axial mass extraction is small, but it can play a role in the future, when more precise measurements of the neutrino-nucleon cross-sections will be performed.…”

Measurement of the Muon Neutrino Inclusive Charged Current Cross Section on Iron using the MINOS Detector

“…The curves are theoretical predictions from the model utilized in Ref [8]. The model assumes an axial mass of M A = 0.999 ± 0.011 GeV.…”

“…The model assumes an axial mass of M A = 0.999 ± 0.011 GeV. (taken from Ref [8]). Similar observations are made in neutrino-nucleon scattering.…”