Neutrino energy reconstruction from one-muon and one-proton events

We propose a method of selecting a high-purity sample of charged current quasielastic neutrino interactions to obtain a precise reconstruction of the neutrino energy. The performance of the method was verified with several tests using genie, neut, and nuwro Monte Carlo event generators with both carbon and argon targets. The method can be useful in neutrino oscillation studies with beams of a few GeV.

Figure 1

Reconstructed initial-state neutron momentum from one-muon and one-proton events for the global relativistic Fermi gas (RFG), local Fermi gas (LFG), and spectral function (SF) nuclear models. The target nucleus is carbon, and the incident neutrino flux is the MiniBooNE ${\nu }_{\mu }$ flux. neut is used to produce the RFG simulation, while nuwro is used for LFG and SF samples. Each sample is normalized to have the same area.

Figure 2

Reconstructed initial-state neutron momentum assuming the default genie RFG model. The target nucleus is carbon, and the incident neutrino flux is the NuMI on-axis ${\nu }_{\mu }$ flux. Contributions from CCQE events and non-CCQE events are shown separately.

Figure 3

Signal acceptance fraction vs background rejection fraction as a function of the cut on reconstructed neutron momentum for $\mathrm{CC}0\pi 1p$ events. Shown are the default configurations of neut (solid black) and genie (solid light gray), as well as nuwro with a local Fermi gas model (solid dark gray) and the spectral function model (dashed dark gray). In all cases, the target nucleus is carbon and the MiniBooNE ${\nu }_{\mu }$ flux is used.

Figure 4

Signal acceptance fraction vs background rejection fraction as a function of a cut on the reconstructed neutron momentum. Shown are predictions from nuwro for both carbon (solid gray) and argon (solid black) assuming a 400 MeV/c proton tracking threshold, and for argon also a curve assuming a lower proton tracking threshold of 200 MeV/c (dashed black).

Figure 5

Neutrino energy resolution for $\mathrm{CC}0\pi 1p$ events, using the CCQE formula (black solid), the method proposed in this paper without (gray solid), and with a cut on the reconstructed neutron momentum at 300 MeV/c (gray dotted). The target nucleus used is argon (a) or carbon (b) and the beam is MiniBooNE's ${\nu }_{\mu }$ (a) and NuMI's on-axis ${\nu }_{\mu }$ (b). The generator used is genie.