Bulletin of the American Physical Society
4th Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Volume 59, Number 10
Tuesday–Saturday, October 7–11, 2014; Waikoloa, Hawaii
Session FM: Neutrino Physics |
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Chair: Timothy Classen, Lawrence Livermore National Laboratory Room: Kona 5 |
Friday, October 10, 2014 9:00AM - 9:15AM |
FM.00001: The COHERENT collaboration: an effort to observe coherent, elastic, neutral-current neutrino-nucleus scattering at the Spallation Neutron Source Grayson Rich The phenomenon of coherent, neutral-current scattering of neutrinos from nuclei was first proposed by D.Z. Freedman in 1974, who posited that an effort to observe this effect experimentally ``may be an act of hubris" owing to extreme experimental difficulties [D.Z. Freedman, Phys. Rev. D. 9, 1974]. Taking advantage of technologies which have come to maturity and new experience gained in the intervening 40 years, the newly-formed COHERENT collaboration seeks to measure for the first time coherent, elastic neutrino-nucleus scattering (CE$\nu$NS). Using neutrinos created by stopped pions at the Spallation Neutron Source (SNS) of Oak Ridge National Laboratory, several detector systems will be deployed to limit systematic uncertainties and unambiguously observe the $N^2$-dependence on the cross section. The current status of the efforts of the collaboration will be addressed, focusing on detector technologies and calibration of these detectors for low-energy nuclear recoils. We will also discuss the longer-term physics goals of the collaboration, including astrophysical implications of the measurements and the use CE$\nu$NS as a probe to search for non-standard neutrino interactions and as a way to measure the weak mixing angle. [Preview Abstract] |
Friday, October 10, 2014 9:15AM - 9:30AM |
FM.00002: Background Studies for an Experimental Neutrino Program at the Spallation Neutron Source for the COHERENT Collaboration Jason Newby The Spallation Neutron Source at the Oak Ridge National Laboratory is a copious producer of neutrinos with multiple flavors, energies and timing structure ideally suited to conduct a broad range of neutrino measurements. Toward this goal of performing neutrino experiments, the recently formed COHERENT collaboration is measuring fast neutron backgrounds within the SNS target building and modeling multiple relevant detector technologies. While the collaboration has identified a rich multi-phased multi-nucleus experimental program, preparations are underway for a near-term observation of coherent elastic neutrino-nuclear scattering with at least one of three maturing detector development efforts within the collaboration. We will outline the proposed experimental program and present the results of our backgrounds measurement campaign and their implications for the feasibility and optimization for the neutrino experimental program. [Preview Abstract] |
Friday, October 10, 2014 9:30AM - 9:45AM |
FM.00003: Fast Neutron Measurements at the Fermilab Booster Neutrino Beam for a Coherent Elastic Neutrino Nucleus Scattering (CENNS) Experiment Robert Cooper Low energy neutrinos ($<$ 50 MeV) can engage in coherent elastic scattering with low momentum transfer on nuclear targets. Coherent scattering is important in supernovae, low-$Q^2$ probes of nuclear form factors, and low-energy tests of the Standard Model. Despite the largest low-energy neutrino cross section, it has remained unobserved because of its low energy deposition and neutron backgrounds. The CENNS collaboration proposes to deploy a 1-ton-scale, single-phase, liquid argon scintillation detector near the Fermilab Booster Neutrino Beam (BNB) for a first measurement. By placing the detector near the beam target far off-axis, a low-energy flux of stopped-pion neutrinos is produced. The proximity to the BNB produces beam-correlated neutron backgrounds whose elastic scatters are indistinguishable from the neutrino signal. In this talk, I will describe CENNS and our previous neutrons measurements near the BNB. I will also highlight our current campaign to map the neutron energy and direction spectrum at the BNB while modulating a series of concrete neutron shields around our neutron detectors. The results will be used to design a neutron shield for a first CENNS measurement. [Preview Abstract] |
Friday, October 10, 2014 9:45AM - 10:00AM |
FM.00004: $^{7}$Be Solar Neutrino Measurement with KamLAND Christopher Grant KamLAND is a multipurpose, 1-kton liquid scintillation detector located in the Kamioka underground laboratory, in Japan. Two distinct liquid scintillator purification campaigns were performed in 2007 and 2008-2009, where the background event rates from decays of $^{85}$Kr, $^{210}$Bi, and $^{210}$Po were reduced by factors of 6$\times$10$^{-6}$, 8$\times$10$^{-4}$, and 5$\times$10$^{-2}$, respectively. This dramatic suppression of low-energy backgrounds increased KamLAND's sensitivity to new physics below 1 MeV. We report a measurement of the 862 keV $^{7}$Be solar neutrino flux with KamLAND, thereby providing the first independent cross-check of this important quantity. The details of the solar neutrino analysis will be presented, along with a comparison to Standard Solar Model flux predictions. [Preview Abstract] |
Friday, October 10, 2014 10:00AM - 10:15AM |
FM.00005: Precision Results on $\theta_{13}$ from Daya Bay Jim Napolitano The Daya Bay Reactor Neutrino Experiment measures the neutrino mixing angle $\theta_{13}$ with high sensitivity, using functionally identical detectors at appropriate distances from the cores of a nuclear power plant. We have analyzed 217 days of data with six detectors, and 404 days with the full complement of eight detectors, obtaining a sample of over two million $\bar\nu_ep\to e^+n$ events. Combining rate and spectral shape information, we find $\sin^22\theta_{13}=0.084\pm0.005$ and $\Delta m^2_{ee}=\left(2.44^{+0.10}_{-0.11}\right)\times10^{-3}$~eV$^2$ for events where the neutron captures on gadolinium. Also, using the six detector data set and a rate analysis based on $np$ capture, we find $\sin^22\theta_{13}=0.083\pm0.018$. We will present details of these results, including a discussion of backgrounds and systematic uncertainties. [Preview Abstract] |
Friday, October 10, 2014 10:15AM - 10:30AM |
FM.00006: New results from RENO Seon-Hee Seo Neutrino oscillation is well known but one of the oscillation parameters, $\theta_{13}$, has not been well measured until 2012. The main goal of RENO (Reactor Experiment for Neutrino Oscillation) is to measure the $\theta_{13}$ using reactor neutrinos. RENO is located in Yonggwang, South Korea, where there are six reactor cores with a total of 16.5 GW$_{\mathrm{th}}$. By detecting the electron anti-neutrinos from nuclear fission processes from the reactors, RENO measured (4.9 sigma) the $\theta_{13}$ in 2012 with 220 live days of data. Since then we have been updating our results more precisely with increased statistics and improved systematics. In this talk, we would like to present our new results (800 live days of data) obtained by a shape analysis method. Excess of neutrino-like events at 5 MeV seen in our data is also discussed. [Preview Abstract] |
Friday, October 10, 2014 10:30AM - 10:45AM |
FM.00007: Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay Karsten Heeger The Daya Bay reactor experiment uses eight antineutrino detectors deployed in three underground experimental halls at distances of about 0.4-2\,km to detect electron antineutrinos from six commercial power reactors. Daya Bay has made a precision measurement of the neutrino oscillation parameters sin$^22\theta_{13}$ and $\Delta m^2_{ee}$ by measuring the relative difference in neutrino interaction rates between detectors in near and far experimental halls. Using data from three antineutrino detectors in the near experimental halls Daya Bay has recently made a high-statistics measurement of the reactor antineutrino spectrum. We will present Daya Bay's flux and spectrum measurement including the comparison to different flux models and methods for extracting a generic reactor antineutrino spectrum. [Preview Abstract] |
Friday, October 10, 2014 10:45AM - 11:00AM |
FM.00008: Spectral Structure of Antineutrinos from Nuclear Reactors Dan Dwyer, Tom Langford We reexamine calculations of energy spectrum of antineutrinos from nuclear reactors. Ab initio calculations rely on our collected knowledge of the nuclear processes involving $\sim$1000 isotopes present within a reactor. While this approach suffers from systematic uncertainties which are difficult to quantify, certain characteristics of the spectrum can be predicted. We examine these characteristics in light of recent high-statistics measurements of positrons from antineutrino inverse beta decay. Impacts on future measurements of reactor antineutrinos will also be discussed. [Preview Abstract] |
Friday, October 10, 2014 11:00AM - 11:15AM |
FM.00009: MicroBooNE Thomas Strauss The MicroBooNE experiment is a neutrino detector located on the Fermilab Booster Neutrino Beamline. The experiment will use a liquid argon time projection chamber (LArTPC) to investigate the nature of the yet unexplained event excess observed by the MiniBooNE collaboration at low reconstructed neutrino energies. LArTPC's allow a detailed study of the energy deposition in showers and thus MicroBooNE will be able to distinguish if the excess is due to single electrons from electron neutrinos or caused by an electron-positron pair created in a gamma conversion from the prominent neutral pion background. The fine-grained tracking capabilities and calorimetric range of the detector will also allow neutrino cross section measurements at $\sim$1GeV in liquid argon, as well as a probe of final-state interactions and other nuclear effects in neutrino interactions in argon with high precision. The TPC has a volume of about 80 tons, and is currently in the final commissioning stages. This talk will present the detector design, construction, the calibration methods used and the current status of the experiment. [Preview Abstract] |
Friday, October 10, 2014 11:15AM - 11:30AM |
FM.00010: Effective Spectral Function for Quasielastic Scattering on Nuclei Arie Bodek, M. Eric Christy, Brian Coopersmith Spectral functions that are used in neutrino event generators (such as GENIE, NEUT, NUANCE, NUWRO, and GiBUU) to model quasielastic (QE) scattering from nuclear targets include Fermi gas, Local Thomas Fermi gas (LTF), Bodek-Ritche Fermi gas with high momentum tail, and the Benhar Fantoni two dimensional spectral function. We find that the predictions of these spectral functions for the $\frac{d\sigma}{d\nu}$ distribution of QE events are in disagreement with the prediction of the $\psi'$ superscaling function which is extracted from fits to quasielastic electron scattering data on nuclear targets. It is known that spectral functions do not fully describe quasielastic scattering because they only model the initial state. Final state interactions distort the shape of $\frac{d\sigma}{d\nu}$, reduce the cross section at the peak and increase the cross section at the tails of the distribution. We show that the kinematic distributions predicted by the $\psi'$ superscaling formalism can be well described with a modified {\it {effective spectral function}} (EFS). [Preview Abstract] |
Friday, October 10, 2014 11:30AM - 11:45AM |
FM.00011: Quasi-Elastic Scattering with Neutrinos in MINERvA Jyotsna Osta, Kenyi Hurtado MINERvA is a few GeV neutrino-nucleus scattering experiment designed to study low energy neutrino interactions both in support of neutrino oscillation experiments as well as a pure weak probe of the nuclear medium. The experiment uses a fine-grained, high resolution detector. The active region is composed of plastic scintillator with additional targets of helium, carbon, iron, lead and water placed upstream of the active region. We present preliminary results from the double differential cross section analysis that aims to study quasi-elastic scattering of neutrinos in the phase space of the muon transverse and longitudinal momenta. This analysis uses the low energy neutrino dataset recorded from November 2009 to April 2012. [Preview Abstract] |
Friday, October 10, 2014 11:45AM - 12:00PM |
FM.00012: ABSTRACT WITHDRAWN |
Friday, October 10, 2014 12:00PM - 12:15PM |
FM.00013: The DCTPC Fast Neutron Detector Marjon Moulai The Double Chooz Time Projection Chamber (DCTPC) project employs a set of directional fast neutron detectors that measure background neutron production at the Double Chooz reactor-based neutrino oscillation experiment's near (120 mwe) and far (300 mwe) halls. The DCTPC detectors are used to study the relationship between fast neutron production and rainfall, and will provide valuable neutron measurements as a function of depth, direction, and energy. I will present the latest results from the 60 liter DCTPC detector and discuss future opportunities with the device. [Preview Abstract] |
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