Processes discussed here are important because they

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Unformatted text preview: in INjector ExpeRiment: nu-A (MINERA), Main Injector Neutrino Oscillation Search (MINOS), Neutrino Joseph A. Formaggio and G. P. Zeller: From eV to EeV: Neutrino cross sections . . . 1324 Oscillation MAgnetic Detector (NOMAD), SciBar Booster Neutrino Experiment (SciBooNE), and Tokai to Kamioka experiment (T2K) have started to study this intermediate energy region in greater detail. New theoretical approaches have also recently emerged. We start by describing the key processes which can contribute to the total cross section at these intermediate neutrino energies. Here we focus on several key processes: quasielastic, NC elastic scattering, resonant single pion production, coherent pion production, multipion production, and kaon production before turning our discussion to deep inelastic scattering in the following section on high-energy neutrino interactions. For comparison, we also include predictions from the NUANCE event generator (Casper, 2002), chosen as a representative of the type of models used in modern neutrino experiments to describe this energy region. The bulk of our discussions center around measurements of  -nucleon scattering. Many of these arguments also carry over to  scattering, except for one key difference; the energy threshold for the reaction. Unlike for the muon case, the charged current  interaction cross section is severely altered because of the large  lepton mass. Figure 10 reflects some of the large differences in the cross section that come about due to this threshold energy. A. Quasielastic scattering For neutrino energies less than $2 GeV, neutrino-hadron interactions are predominantly quasielastic (QE), hence they provide a large source of signal events in many neutrino oscillation experiments operating in this energy range. In a QE interaction, the neutrino scatters off an entire nucleon rather than its constituent partons. In a charged current neutrino QE interaction, the target neutron is converted to a proton. In the case of an antineutrino scattering, the target proton is converted into a neutron,  n ! À p;  p ! þ n: " (56) cross section / E (10-38 cm2 / GeV) Such simple interactions were extensively studied in the 1970s–1990s primarily using deuterium-filled bubbble chambers. The main interest at the time was in testing the vectoraxial vector (V-A) nature of the weak interaction and in 1.4 1.2 1 µ 0.8 0.6 0.4 0.2 0 10 -1 1 10 10 2 E (GeV) FIG. 10. Plot comparing the total charged current  (solid) and  (dashed) per nucleon cross sections divided by neutrino energy and plotted as a function of neutrino energy. Rev. Mod. Phys., Vol. 84, No. 3, July–September 2012 measuring the axial-vector form factor of the nucleon, topics that were considered particularly important in providing an anchor for the study of NC interactions (Sec. V.B). As examples, Singh and Oset (1992) and Lyubushkin et al. (2009) provided valuable summaries of some of these early QE investigations. In predicting the QE...
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