The ArgoNeuT Collaboration reports the first measurement of neutral current pi(0) production in nu(mu)-argon and (nu) over bar (mu)-argon scattering. This measurement was performed using the ArgoNeuT liquid argon time projection chamber deployed at Fermilab's NuMI neutrino beam with an exposure corresponding to 1.2 x 10(20) protons-on-target from the Fermilab main injector and a mean energy for nu(mu) of 9.6 GeV and for (nu) over bar (mu) of 3.6 GeV. We compare the measured cross section and kinematic distributions to predictions from the GENIE and NuWro neutrino interaction event generators.

The ArgoNeuT collaboration reports the first measurement of neutral current $$\pi^{0}$$ production in $$\nu_{\mu}$$-argon and $$\bar{\nu}_{\mu}$$-argon scattering. This measurement was performed using the ArgoNeuT liquid argon time projection chamber deployed at Fermilab's NuMI neutrino beam with an exposure corresponding to 1.2$$\times 10^{20}$$ protons-on-target from the Fermilab Main Injector and a mean energy for $$\nu_{\mu}$$ of 9.6~GeV and for $$\bar{\nu}_{\mu}$$ of 3.6~GeV. We compare the measured cross section and kinematic distributions to predictions from the GENIE and NuWro neutrino interaction event generators.

Received 6 January 2015DOI:https://doi.org/10.1103/PhysRevLett.114.039901© 2015 American Physical Society

The ArgoNeuT collaboration reports the first measurement of neutral current π^0 production in ν_μ-argon and ν̅_μ-argon scattering. This measurement was performed using the ArgoNeuT liquid argon time projection chamber deployed at Fermilab's NuMI neutrino beam with an exposure corresponding to 1.2× 10^20 protons-on-target from the Fermilab Main Injector and a mean energy for ν_μ of 9.6 GeV and for ν̅_μ of 3.6 GeV. We compare the measured cross section and kinematic distributions to predictions from the GENIE and NuWro neutrino interaction event generators.

We report on the first cross section measurements for charged current coherent pion production by neutrinos and antineutrinos on argon. These measurements are performed using the ArgoNeuT detector exposed to the NuMI beam at Fermilab. The cross sections are measured to be 2.6(-1.0)(+1.2)(stat)(-0.4)(+0.3)(syst)×10(-38)  cm(2)/Ar for neutrinos at a mean energy of 9.6 GeV and 5.5(-2.1)(+2.6)(stat)(-0.7)(+0.6)(syst)×10(-39)  cm(2)/Ar for antineutrinos at a mean energy of 3.6 GeV.

Short range nucleon-nucleon correlations in nuclei (NN SRC) carry important information on nuclear structure and dynamics. NN SRC have been extensively probed through two-nucleon knockout reactions in both pion and electron scattering experiments. We report here on the detection of two-nucleon knockout events from neutrino interactions and discuss their topological features as possibly involving NN SRC content in the target argon nuclei. The ArgoNeuT detector in the Main Injector neutrino beam at Fermilab has recorded a sample of 30 fully reconstructed charged-current events where the leading muon is accompanied by a pair of protons at the interaction vertex, 19 of which have both protons above the Fermi momentum of the Ar nucleus. Out of these 19 events, four are found with the two protons in a strictly back-to-back high momenta configuration directly observed in the final state and can be associated to nucleon resonance pionless mechanisms involving a pre-existing short range correlated np pair in the nucleus. Another fraction (four events) of the remaining 15 events has a reconstructed back-to-back configuration of an np pair in the initial state, a signature compatible with one-body quasielastic interaction on a neutron in a short range correlation (SRC) pair. The detection of these two subsamples of the collected (mu(-) + 2p) events suggests that mechanisms directly involving nucleon-nucleon SRC pairs in the nucleus are active and can be efficiently explored in neutrino-argon interactions with the Liquid Argon Time Projection chamber technology.

Electron recombination in highly ionizing stopping protons and deuterons is studied in the ArgoNeuT detector. The data are well modeled by either a Birks model or a modified form of the Box model. The dependence of recombination on the track angle with respect to the electric field direction is much weaker than the predictions of the Jaffe columnar theory and by theoretical-computational simulations.

ArgoNeuT, or Argon Neutrino Test, is a 170 liter liquid argon time projection chamber designed to collect neutrino interactions from the NuMI beam at Fermi National Accelerator Laboratory. ArgoNeuT operated in the NuMI low-energy beam line directly upstream of the MINOS Near Detector from September 2009 to February 2010, during which thousands of neutrino and antineutrino events were collected. The MINOS Near Detector was used to measure muons downstream of ArgoNeuT. Though ArgoNeuT is primarily an R D project, the data collected provide a unique opportunity to measure neutrino cross sections in the 0.1-10 GeV energy range. Fully reconstructing the muon from these interactions is imperative for these measurements. This paper focuses on the complete kinematic reconstruction of neutrino-induced through-going muons tracks. Analysis of this high statistics sample of minimum ionizing tracks demonstrates the reliability of the geometric and calorimetric reconstruction in the ArgoNeuT detector.

The ArgoNeuT liquid argon time projection chamber has collected thousands of neutrino and anti-neutrino events during an extended run period in the NuMI beam-line at Fermilab. This paper focuses on the main aspects of the detector layout and related technical features, including the cryogenic equipment, time projection chamber, read-out electronics, and off-line data treatment. The detector commissioning phase, physics run, and first neutrino event displays are also reported. The characterization of the main working parameters of the detector during data-taking, the ionization electron drift velocity and lifetime in liquid argon, as obtained from through-going muon data complete the present report.

The Proceedings of the 2011 workshop on Fundamental Physics at the Intensity Frontier. Science opportunities at the intensity frontier are identified and described in the areas of heavy quarks, charged leptons, neutrinos, proton decay, new light weakly-coupled particles, and nucleons, nuclei, and atoms.

The ArgoNeuT Collaboration presents the first measurements of inclusive muon neutrino charged current differential cross sections on argon. Obtained in the NuMI neutrino beam line at Fermilab, the flux-integrated results are reported in terms of outgoing muon angle and momentum. The data are consistent with the Monte Carlo expectation across the full range of kinematics sampled, 0°<θ(μ)<36° and 0<P(μ)<25 GeV/c. Along with confirming the viability of liquid argon time projection chamber technology for neutrino detection, the measurements allow tests of low-energy neutrino scattering models important for interpreting results from long baseline neutrino oscillation experiments designed to investigate CP violation and the orientation of the neutrino mass hierarchy.

Particle physics aims to understand the universe around us. The Standard Model of particle physics describes the basic structure of matter and forces, to the extent we have been able to probe thus far. However, it leaves some big questions unanswered. Some are within the Standard Model itself, such as why there are so many fundamental particles and why they have different masses. In other cases, the Standard Model simply fails to explain some phenomena, such as the observed matter-antimatter asymmetry in the universe, the existence of dark matter and dark energy, and the mechanism that reconciles gravity with quantum mechanics. These gaps lead us to conclude that the universe must contain new and unexplored elements of Nature. Most of particle and nuclear physics is directed towards discovering and understanding these new laws of physics. These questions are best pursued with a variety of approaches, rather than with a single experiment or technique. Particle physics uses three basic approaches, often characterized as exploration along the cosmic, energy, and intensity frontiers. Each employs different tools and techniques, but they ultimately address the same fundamental questions. This allows a multi-pronged approach where attacking basic questions from different angles furthers knowledge and providesmore » deeper answers, so that the whole is more than a sum of the parts. A coherent picture or underlying theoretical model can more easily emerge, to be proven correct or not. The intensity frontier explores fundamental physics with intense sources and ultra-sensitive, sometimes massive detectors. It encompasses searches for extremely rare processes and for tiny deviations from Standard Model expectations. Intensity frontier experiments use precision measurements to probe quantum effects. They typically investigate very large energy scales, even higher than the kinematic reach of high energy particle accelerators. The science addresses basic questions, such as: Are there new sources of CP violation? Is there CP violation in the leptonic sector? Are neutrinos their own antiparticles? Do the forces unify? Is there a weakly coupled hidden sector that is related to dark matter? Do new symmetries exist at very high energy scales? To identify the most compelling science opportunities in this area, the workshop Fundamental Physics at the Intensity Frontier was held in December 2011, sponsored by the Office of High Energy Physics in the US Department of Energy Office of Science. Participants investigated the most promising experiments to exploit these opportunities and described the knowledge that can be gained from such a program. The workshop generated much interest in the community, as witnessed by the large and energetic participation by a broad spectrum of scientists. This document chronicles the activities of the workshop, with contributions by more than 450 authors. The workshop organized the intensity frontier science program along six topics that formed the basis for working groups: experiments that probe (i) heavy quarks, (ii) charged leptons, (iii) neutrinos, (iv) proton decay, (v) light, weakly interacting particles, and (vi) nucleons, nuclei, and atoms. The conveners for each working group included an experimenter and a theorist working in the field and an observer from the community at large. The working groups began their efforts well in advance of the workshop, holding regular meetings and soliciting written contributions. Specific avenues of exploration were identified by each working group. Experiments that study rare strange, charm, and bottom meson decays provide a broad program of measurements that are sensitive to new interactions. Charged leptons, particularly muons and taus, provide a precise probe for new physics because the Standard Model predictions for their properties are very accurate. Research at the intensity frontier can reveal CP violation in the lepton sector, and elucidate whether neutrinos are their own antiparticles. A very weakly coupled hidden-sector that may comprise the dark matter in the universe could be discovered. The search for proton decay can probe the unification of the forces with unprecedented reach and test sacrosanct symmetries to very high scales. Detecting an electric dipole moment for the neutron, or neutral atoms, could establish a clear signal for new physics, while limits on such a measurement would place severe constraints on many new theories. This workshop marked the first instance where discussion of these diverse programs was held under one roof. As a result, it was realized that this broad effort has many connections; a large degree of synergy exists between the different areas and they address similar questions. Results from one area were found to be pertinent to experiments in another domain.« less

The status of Fixed Target experiments to study charm and bottom is reviewed. The physics motivation for further high statistics studies of charm and bottom is presented. The technical challenges which will be encountered in doing very high sensitivity studies are described, some possible solutions are offered, and areas where additional research and development are required and identified. 38 refs., 8 figs., 9 tabs.