NEUT development for T2K and relevance of updated 2p2h models

The MiniBooNE large axial-mass anomaly has motivated the development of new theoretical Charged Current Quasi-Elastic (CCQE) cross-section models in recent years. These proceedings review the development of the neutrino simulation generator NEUT to incorporate these more sophisticated CCQE models, including multi-nucleon interaction (2p2h) effects. The fit results on the MINER$\nu$A and MiniBoone data are used to tune neutrino interaction models in NEUT and develop a default cross-section model for T2K.Comment: Contribution to the proceedings of the 16th International Workshop on Neutrino Factories and Future Neutrino Beam Facilities, 25-30 August, 2014, University of Glasgow, United Kingdo

Using MiniBooNE neutral current elastic cross section results to constrain 3+1 sterile neutrino models

The MiniBooNE Neutral Current Elastic (NCEL) cross section results are used to extract limits in the $\Delta m^{2}-\sin^{2}\vartheta_{\mu s}$ plane for a 3+1 sterile neutrino model with a mass splitting $0.1 \leq \Delta m^{2} \leq 10.0$ eV$^{2}$. GENIE is used with a cross section model close to the one employed by MiniBooNE to make event rate predictions using simulations on the MiniBooNE target material CH$_{2}$. The axial mass is a free parameter in all fits. Sterile modifications to the flux and changes to the cross section in the simulation relate the two and allow limits to be set on sterile neutrino mixing using cross section results. The large axial mass problem makes it necessary for experiments to perform their own axial mass fits, but a prior fit to the same dataset could mask a sterile oscillation signal if the sterile and cross section model parameters are not independent. We find that for the NCEL dataset there are significant correlations between the sterile and cross section model parameters, making a fit to both models simultaneously necessary to get robust results. Failure to do this results in stronger than warranted limits on the sterile parameters. The general problems that the current uncertainty on charged-current quasi-elastic (CCQE) and NCEL cross sections at MiniBooNE energies pose for sterile neutrino measurements are discussed.Comment: Final version accepted for publication in JHE

Using MiniBooNE NCEL and CCQE cross section results to constrain 3+1 sterile neutrino models

The MiniBooNE NCEL and CCQE cross-section measurements (neutrino running) are used to set limits in the $\Delta m^{2}-\sin^{2}\vartheta_{\mu s}$ plane for a 3+1 sterile neutrino model with a mass splitting $0.1 \leq \Delta m^{2} \leq 10.0$ eV$^{2}$. GENIE is used, with a relativistic Fermi gas model, to relate $E_{\nu}$ and the reconstructed quantities measured. The issue of uncertainty in the underlying cross-section model and its effect on the sterile neutrino limits is explored, and robust sterile neutrino limits are produced by fitting the sterile parameters and the axial-mass cross-section parameter simultaneously.Comment: Contribution to the Proceedings of the NuPhys2013 Conference: Prospects in Neutrino Physics, 19-20 December 2013, IOP, Londo

Constraining the GENIE model of neutrino-induced single pion production using reanalyzed bubble chamber data

The longstanding discrepancy between bubble chamber measurements of $\nu_\mu$-induced single pion production channels has led to large uncertainties in pion production cross section parameters for many years. We extend the reanalysis of pion production data in deuterium bubble chambers where this discrepancy is solved (Wilkinson et al., PRD 90 (2014) 112017) to include the $\nu_{\mu}n\rightarrow \mu^{-}p\pi^{0}$ and $\nu_{\mu}n\rightarrow \mu^{-}n\pi^{+}$ channels, and use the resulting data to fit the parameters of the GENIE (Rein-Sehgal) pion production model. We find a set of parameters that can describe the bubble chamber data better than the GENIE default parameters, and provide updated central values and reduced uncertainties for use in neutrino oscillation and cross section analyses which use the GENIE model. We find that GENIE's non-resonant background prediction has to be significantly reduced to fit the data, which may help to explain the recent discrepancies between simulation and data observed by the MINERvA coherent pion and NOvA oscillation analyses.Comment: v3: Updated to match published versio

A tolerable candle: the low-ν\nu method with LHC neutrinos

The Forward Physics Facility (FPF) plans to use neutrinos produced at the Large Hadron Collider (LHC) to make a variety of measurements at previously unexplored TeV energies. Its primary goals include precision measurements of the neutrino cross section and using the measured neutrino flux both to uncover information about far-forward hadron production and to search for various beyond standard model scenarios. However, these goals have the potential to conflict: extracting information about the flux or cross section relies upon an assumption about the other. In this manuscript, we demonstrate that the FPF can use the low-$\nu$ method -- a technique for constraining the flux shape by isolating neutrino interactions with low energy transfer to the nucleus -- to break this degeneracy. We show that the low-$\nu$ method is effective for extracting the $\nu_{\mu}$ flux shape, in a model-independent way. We discuss its application for extracting the $\bar{\nu}_{\mu}$ flux shape, but find that this is significantly more model dependent. Finally, we explore the precision to which the $\nu_{\mu}$ flux shape could be constrained at the FPF, for a variety of proposed detector options. We find that the precision would be sufficient to discriminate between various realistic flux models