We present a study of neutrino-nucleus interactions at the T2K experiment based on the GiBUU transport model. The aim of T2K is to measure $ u_e$ appearance and $theta_{13}$, but it will also be able to do a precise measurement of $ u_mu$ disappearan
ce. The former requires a good understanding of $pi^0$ production while the latter is closely connected with a good understanding of quasielastic scattering. For both processes we investigate the influence of nuclear effects and particular final-state interactions on the expected event rates taking into account the T2K detector setup.
We apply the GiBUU model to questions relevant for current and future neutrino long-baseline experiments, we address in particular the relevance of charged-current reactions for neutrino disappearance experiments. A correct identification of charged-
current quasielastic (CCQE) events - which is the signal channel in oscillation experiments - is relevant for the neutrino energy reconstruction and thus for the oscillation result. We show that about 20% of the quasielastic cross section is misidentified in present-day experiments and has to be corrected for by means of event generators. Furthermore, we show that also a significant part of 1pi+ (> 40%) events is misidentified as CCQE mainly caused by the pion absorption in the nucleus. We also discuss the dependence of both of these numbers on experimental detection thresholds. We further investigate the influence of final-state interactions on the neutrino energy reconstruction.
We investigate charged and neutral current neutrino-induced incoherent pion production off nuclei within the GiBUU model at energies relevant for the MiniBooNE and K2K experiments. Special attention is paid to the entanglement between measured CCQE a
nd CC1pi+ cross sections. We further give predictions and compare to recent data measured at MiniBooNE.
All available theoretical estimates of neutrino-induced coherent pion production rely on the local approximation for the Delta propagator. The validity of this approximation is scrutinized. It is found that the local approximation overestimates the n
eutrino-induced coherent pion production on nuclei significantly, by up to 100%.
We present the GiBUU model for neutrino nucleus scattering: assuming impulse approximation, this reaction is treated as a two step process. In the initial state step, the neutrinos interact with bound nucleons. In the final state step, the outgoing p
articles of the initial reaction are propagated through the nucleus and undergo final state interactions. In this contribution, we focus on the validation of the initial and final state interaction treatment in GiBUU using experimental data for pion-nucleus, photon-nucleus and electron-nucleus scattering.
We investigate charged and neutral current neutrino induced incoherent pion production off nuclei at MiniBooNE and K2K energies within the GiBUU model. We assume impulse approximation and treat the nucleus as a local Fermi gas of nucleons bound in a
mean-field potential. In-medium spectral functions are also taken into account. The outcome of the initial neutrino nucleon reaction undergoes complex hadronic final state interactions. We present results for neutral current pi^0 and charged current pi^+ production and compare to MiniBooNE and K2K data.
We present a model for electron- and neutrino-scattering off nucleons and nuclei focussing on the quasielastic and resonance region. The lepton-nucleon reaction is described within a relativistic formalism that includes, besides quasielastic scatteri
ng, the excitation of 13 N* and Delta resonances and a non-resonant single-pion background. Recent electron-scattering data is used for the state-of-the-art parametrizations of the vector form factors; the axial couplings are determined via PCAC and, in the case of the Delta resonance, the axial form factor is refitted using neutrino-scattering data. Scattering off nuclei is treated within the GiBUU framework that takes into account various nuclear effects: the local density approximation for the nuclear ground state, mean-field potentials and in-medium spectral functions. Results for inclusive scattering off Oxygen are presented and, in the case of electron-induced reactions, compared to experimental data and other models.
It is pointed out that so far all theoretical estimates of coherent pion production off nuclei induced by neutrinos rely on the local approximation well known in photonuclear physics. The effects of dropping this approximation are discussed. It is fo
und that in a plane wave approximation for the pion the local approximation overestimates the coherent neutrino-induced pion production on nuclei.
Current long baseline experiments aim at measuring neutrino oscillation parameters with a high precision. A critical quantity is the neutrino energy which can not be measured directly but has to be reconstructed from the observed hadrons. A good know
ledge of neutrino-nucleus interactions is thus necessary to minimize the systematic uncertainties in neutrino fluxes, backgrounds and detector responses. In particular final-state interactions inside the target nucleus modify considerably the particle yields through rescattering, charge-exchange and absorption. Nuclear effects can be described with our coupled channel GiBUU transport model where the neutrino first interacts with a bound nucleon producing secondary particles which are then transported out of the nucleus. In this contribution, we give some examples for the application of our model focusing in particular on the MiniBooNE and K2K experiments.
