Neutrino energy reconstruction from one muon and one proton events

We propose a new method of selection of high purity charge current quasielastic neutrino events with a good reconstruction of interacting neutrino energy. Performance of the method was verified with several tests using GENIE, NEUT and NuWro Monte Carlo events generators with carbon and argon targets. The method can be useful in neutrino oscillation studies with a few GeV energy beams.Comment: 8 pages, 5 figure

Charged-current Quasi-elastic-like neutrino interactions at the T2K experiment

T2K is a long-baseline neutrino oscillation experiment based in Japan. The experiment has already measured the appearance of ⌫e in a ⌫μ beam, and is hoping to measure the appearance of ⌫¯e in a ⌫¯μ beam, which would open the possibility of observing CP-violation in the lepton sector. The charged current quasi-elastic (CCQE) interaction (vμ + n -> μ− + p) is of great importance to T2K as it is expected to make up over 80% of the interactions at the oscillation peak (600 MeV). In recent years it has become clear that the most common model describing CCQE interactions on nuclei, the Relativistic Fermi Gas (RFG) model, is not able to describe low energy data on nuclear targets. An alternative model, the Spectral Function (SF) model, was implemented in the NEUT interaction generator. Relevant uncertainties in this model are identified and evaluated. The charged current quasi-elastic-like cross section is then measured using the T2K near detector, ND280, as a function of muon momentum and angle. This data is then critically compared to the predictions from two implementations of the RFG model, and also to the newly implemented SF model. The total integrated cross section is found to be (4.06 ± 0.757) x 10−39 cm2 nucleon−1. This value is currently in agreement with all three predictions

Observation of electron neutrino appearance in a muon neutrino beam

The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm232 and a CP violating phase δCP. In this neutrino oscillation scenario, assuming |Δm232|=2.4×10−3  eV2, sin2θ23=0.5, and Δm232>0 (Δm232<0), a best-fit value of sin22θ13=0.140+0.038−0.032 (0.170+0.045−0.037) is obtained at δCP=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ13 from reactor experiments, some values of δCP are disfavored at the 90% C.L

Recent results from the T2K experiment

The Tokai to Kamioka (T2K) experiment studies neutrino oscillations using a beam of muon neutrinos produced by an accelerator. The neutrinos travel from J-PARC on the east coast of Japan and are detected 295 kilometers further away in the Super-Kamiokande detector. A complex of near detectors located 280 meters away from the neutrino production target is used to better characterize the neutrino beam and reduce systematic uncertainties. The experiment aims at measuring electronic neutrino appearance (νμ→νe oscillation) to measure the neutrino mixing angle θ13, and muon neutrino disappearance to measure the neutrino mixing angle θ23 and mass splitting |View the MathML source|. We report here electron neutrino appearance results using three years of data, recorded until the 2012 summer, as well as muon neutrino disappearance results based on the data coming from the first two years of the experiment

Measurement of the inclusive νμ charged current cross section on carbon in the near detector of the T2K experiment

T2K has performed the first measurement of νμ inclusive charged current interactions on carbon at neutrino energies of ∼1  GeV where the measurement is reported as a flux-averaged double differential cross section in muon momentum and angle. The flux is predicted by the beam Monte Carlo and external data, including the results from the NA61/SHINE experiment. The data used for this measurement were taken in 2010 and 2011, with a total of 10.8×1019 protons-on-target. The analysis is performed on 4485 inclusive charged current interaction candidates selected in the most upstream fine-grained scintillator detector of the near detector. The flux-averaged total cross section is ⟨σCC⟩ϕ=(6.91±0.13(stat)±0.84(syst))×10−39  cm2nucleon for a mean neutrino energy of 0.85 GeV

Deep Underground Neutrino Experiment (DUNE) Near Detector Conceptual Design Report

International audienceThe Deep Underground Neutrino Experiment (DUNE) is an international, world-class experiment aimed at exploring fundamental questions about the universe that are at the forefront of astrophysics and particle physics research. DUNE will study questions pertaining to the preponderance of matter over antimatter in the early universe, the dynamics of supernovae, the subtleties of neutrino interaction physics, and a number of beyond the Standard Model topics accessible in a powerful neutrino beam. A critical component of the DUNE physics program involves the study of changes in a powerful beam of neutrinos, i.e., neutrino oscillations, as the neutrinos propagate a long distance. The experiment consists of a near detector, sited close to the source of the beam, and a far detector, sited along the beam at a large distance. This document, the DUNE Near Detector Conceptual Design Report (CDR), describes the design of the DUNE near detector and the science program that drives the design and technology choices. The goals and requirements underlying the design, along with projected performance are given. It serves as a starting point for a more detailed design that will be described in future documents

Reconstruction of interactions in the ProtoDUNE-SP detector with Pandora

International audienceThe Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic essential to the reconstruction of particle interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at ProtoDUNE-SP, a prototype for the Deep Underground Neutrino Experiment far detector. ProtoDUNE-SP, located at CERN, is exposed to a charged-particle test beam. This paper gives an overview of the Pandora reconstruction algorithms and how they have been tailored for use at ProtoDUNE-SP. In complex events with numerous cosmic-ray and beam background particles, the simulated reconstruction and identification efficiency for triggered test-beam particles is above 80% for the majority of particle type and beam momentum combinations. Specifically, simulated 1 GeV/$c$ charged pions and protons are correctly reconstructed and identified with efficiencies of 86.1$\pm0.6$% and 84.1$\pm0.6$%, respectively. The efficiencies measured for test-beam data are shown to be within 5% of those predicted by the simulation