Session T12: Accelerator Neutrino Expts. I

Analysis of Neutral Current $\pi ^{0}$ Events at MiniBooNE

The current generation of neutrino oscillation experiments, such as the MiniBooNE electron neutrino appearance search, require excellent understanding of backgrounds from neutral current $\pi ^{0}$ interactions. The electromagnetic signature of these events mimics that of charged current electron neutrino interactions, producing misidentified signal. This background will continue to be an important consideration for future long baseline electron (anti)neutrino appearance searches. The MiniBooNE experiment has collected the largest sample of neutrino interactions at $\sim $1 GeV and antineutrino interactions overall to date, providing a wealth of data for neutral current $\pi ^{0}$ production measurements. In this talk the current results of the neutral current $\pi ^{0}$ analysis in both neutrino and antineutrino running will be presented.   

Measurement of $\nu_{\mu}$ and $\nu_{e}$ Events in an Off-Axis Neutrino Beam

The purpose of the MiniBooNE detector at Fermilab is to measure neutrinos from the Booster beamline. In the same time the MiniBooNE detector observes off-axis neutrinos from the NuMI/Minos beamline. These events are used to measure pion and kaon components of the NuMI beam. The data sample provide an important complementary analysis of the neutrino spectrum since the energy and distance is similar to the Fermilab Booster beam. We analyzed charged current quasi-elastic ( $\nu_{\mu} n \rightarrow \mu^{-} p$ ) events that dominate at energies below 2 GeV. This sample is used to demonstrate our understanding of the beam. In the next step an enriched $\nu_{e}$ event sample ( $\nu_{e} n \rightarrow e^{-} p$ ) was isolated. The NuMI events are dominated by intrinsic $\nu_{e}$ in low neutrino energy region and therefore subject to different systematics when compared to the Booster neutrinos. The results of the analyses will be presented.   

Predicting the Electron Neutrino Background Components at the MINOS Far Detector

The MINOS experiment has the potential to observe or set more stringent limits on the appearance of electron neutrinos. Critical to the ability to resolve a possible signal is an accurate prediction of the total background from all neutrinos at the MINOS Far Detector. Upon measuring the most significant background components at the MINOS Near Detector, it is possible to extrapolate and predict the number of background events expected at the MINOS Far Detector. The details of these techniques are discussed.   

Studies of the NuMI Neutrino Flux Using the Accompanying Muon Beam

In neutrino oscillation and interaction experiments, uncertainty in the flux of incident particles due to limited understanding of hadron production from nuclear targets is the largest contributor of systematic error to neutrino oscillation and cross-section measurements. We propose to measure the flux generated by the NuMI beam line by measuring the daughter muon flux produced in pion and kaon decays, $\pi\rightarrow\mu\nu_ {\mu}$, K$^{\pm}\rightarrow\mu\nu_{\mu}$ and K$_{L} \rightarrow\pi\mu\nu_{\mu}$, using the muon monitoring system in the beam line. The longitudinal and transverse momentum of parent particles can be varied by moving the target longitudinally with respect to the focusing horns and by varying the current supplied to the horns providing a mechanism to map the momentum space of focused parents. The muon monitoring system consists of 3 arrays of 81 ionization chambers located approximately 720m downstream of the target. Muons must have a minimum energy of 4, 10 and 20GeV to penetrate muon monitor 1, 2 and, 3, respectively. Thus, the three monitors taken together can provide measure of the muon spectrum which is directly related to the parent pion and kaon flux off of the NuMI target.   

High Intensity Neutrino Oscillation Experiments and Exotic Particles

Modern accelerator based neutrino experiments, those currently operating and those being proposed, use very intense beams to produce neutrinos. Those beams greatly surpass previous experiments in the number of protons on target and offer new opportunities for exotic particle searches. This paper discusses the discovery potential of current and future neutrino oscillation beams and experiments for weakly interacting neutral particles such as (pseudo)Goldstone bosons and gauge bosons which result from the spontaneous breakdown of grand unified theories particle physics.   

Eikonal contributions to Ultra High Energy Neutrino-Nucleon Cross Sections in Low Scale Gravity Models

We calculate low scale gravity effects on the cross section for neutrino-nucleon scattering at center of mass energies up to the Greisen-Zatsepin-Kuzmin (GZK) scale, in the eikonal approximation. We compare the cases of an infinitely thin brane embedded in 5 compactified extra-dimensions, and of a brane with a physical tension $M_{S}=1$ TeV and $M_{S}=10$ TeV. The extra dimensional Planck scale is set at $10^{3}$ GeV and $2\times10^{3}$ GeV. We also compare our calculations with pre-existing neutral current standard model calculations in the same energy range. New physics effects enhance the cross section by two order of magnitude on average. Moreover, in the thin brane limit, the full eikonal approximation results in a cross section an order of magnitude higher than in the corresponding saddle point approximation.   

Muon induced neutron study at medium depths underground

Muon induced neutron background is one of the most important backgrounds for many underground experiments, such as dark matter search and neutrino experiments. We have launched an experiment to study muon-induced neutron rate at the Aberdeen Tunnel Laboratory in Hong Kong, which has a 600 m.w.e. overburden. The overburden and rock composition of the Aberdeen Tunnel Laboratory are similar to those of the experiment halls of the Dayabay Reactor Neutrino Oscillation experiment, and thus our results will provide valuable information for the latter. A 650kg Gd-doped liquid scintillator neutron detector with muon tracker is used in this experiment. I will report on the progress of the Aberdeen Tunnel experiment as well as simulation results.   

Liquid Argon Time Projection Chambers: R\&D Towards Kiloton Class Detectors

Liquid Argon Time Projection Chamber (LAr TPC) detectors are ideally suited for studying neutrino interactions and probing the parameters that characterize neutrino oscillations. The ability to drift ionization particles over long distances in purified argon and to trigger on abundant scintillation light allows for excellent particle identification and triggering capability. Recent work in the development of LAr TPC technology for massive kiloton size detectors will be presented in this talk, including details of the ArgoNeuT (Argon Neutrino Test) test-beam project, which is a 175 liter LAr TPC exposed to Fermilab's NuMI neutrino beamline. The first neutrino interactions observed in ArgoNeuT, as well as results from a commissioning run on the surface, will be presented. Proposals for the next generation of LAr TPC experiments, and the issues that must be confronted by these experiments, will be discussed.   

Neutrino Physics and LArTPC R\&D with ArgoNeuT

Set to begin taking data in early 2008 in the on-axis NuMI neutrino beamline, ArgoNeuT is a Liquid Argon Time Projection Chamber (LArTPC) R\&D test stand for future CP Violation and $\theta_{13}$ neutrino oscillation searches. The first LArTPC to be placed in a ``low'' energy accelerator-based neutrino beam, ArgoNeuT will collect $\sim$10$^5$ neutrino events per year in the 0.1-10 GeV range (peaking at 3 GeV). The GEANT4 simulation framework and physics capabilitity of the detector will be presented. Including comparison to first events, simulation discussion will focus on using a dE/dx tag for electron and gamma separation, vital for $\nu_\mu$/$\nu_e$ tagging efficiency. Also, the possibility of $\nu_\mu$ charged current quasi-elastic cross section and M$_A$ parameter measurements will be discussed.