Bulletin of the American Physical Society
2017 Fall Meeting of the APS Division of Nuclear Physics
Volume 62, Number 11
Wednesday–Saturday, October 25–28, 2017; Pittsburgh, Pennsylvania
Session CH: Neutrino Oscillations |
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Chair: Jordan Myslik, Lawrence Berekely National Laboratory Room: Marquis B |
Thursday, October 26, 2017 8:30AM - 8:42AM |
CH.00001: Coincidence (e,e'p) Scattering on 40Ar and 48 Ti to Aid Precision Neutrino Oscillation Experiments Dan Abrams Neutrino oscillations are an active area of research, with experiments such as DUNE (Deep Underground Neutrino Experiment). DUNE will make use of large liquid argon detectors to perform a precision measurement of the CP violating phase. Hence, an understanding of the argon nuclear ground state and its response to (anti-)neutrino interactions is of paramount importance. Information about the nuclear ground state is encapsulated in the spectral function, $S(k,E)$, the joint probability of removing a nucleon of momentum $k = |\textbf{k}|$ from the ground state leaving the residual (A-1) system with excitation energy E. E12-14-012 at Jefferson Lab ran in early 2017 and has measured the argon spectral function through coincidence $(e,e^{\prime}p)$ scattering on $^{40}$Ar and $^{48}$Ti. The results of E12-14-012 are important to both the neutrino and nuclear physics communities. A direct measurement of the coincidence $(e,e^{\prime}p)$ cross section from $^{40}$Ar and $^{48}$Ti will provide valuable information about the argon nucleus, as well as the experimental input necessary to constrain theoretical models used to calculate $S(k,E)$, paving the way for reliable estimates of the neutrino cross sections. Data from E12-14-012 is currently being analyzed at UVA and Va. Tech. [Preview Abstract] |
Thursday, October 26, 2017 8:42AM - 8:54AM |
CH.00002: First results of the liquid-argon time-projection chamber response to medium-energy neutrons and the CAPTAIN program Christopher Mauger The Cryogenic Apparatus for Precision Tests of Argon Interactions with Neutrinos (CAPTAIN) program makes measurements that are crucial for the future DUNE experiment. DUNE aims to study neutrino oscillation phenomena with very high precision with long-baseline and atmospheric neutrinos. In addition, DUNE will measure the time and energy-dependent electron-neutrino spectrum from galactic core-collapse supernovae if the neutrinos pass through the earth during the lifetime of the experiment. CAPTAIN addresses challenges with both of these programs by making measurements of the liquid-argon time-projection chamber (LArTPC) response to medium-energy neutrons and by measuring the electron-neutrino on argon cross-section in an energy regime coincident with the neutrino spectrum expected from core-collapse supernova. First, we have deployed Mini-CAPTAIN, a 400-kg instrumented-mass LArTPC, in a neutron beamline at the Los Alamos Neutron Science Center that provides neutrons of energies up to 800 MeV. I report the first results of these measurements and their implications for DUNE’s long-baseline neutrino oscillation program. I further describe the plans for low-energy neutrino measurements with the 5-ton CAPTAIN detector. [Preview Abstract] |
Thursday, October 26, 2017 8:54AM - 9:06AM |
CH.00003: Three-fold increase of M1 strength in $^{\mathrm{40}}$Ar at 10 MeV excitation energy. Werner Tornow, Sean Finch, FNU Krishichayan, Anton Tonchev We reexamined the excitation energy region of $^{\mathrm{40}}$Ar around 9.8 MeV with the goal of determining the known M1 strength located at 9.76 MeV [1] more accurately. The physics motivation was based on the fact that i) the neutrino-nucleus interaction cross section is proportional to the M1 strength of a nucleus, ii) DUNE, the Deep Underground Neutrino Experiment at SURF will be using liquid argon as detector medium, iii) the energy spectrum of supernova neutrinos is peaked at approximately 10 MeV. Mono-energetic and linearly polarized photons of 9.88 MeV were produced via Compton backscattering of 548 nm FEL photons from 543 MeV electrons at the High-Intensity $\gamma $-ray Source (HI$\gamma $S) facility at TUNL. The 1.25 cm diameter photon beam with energy spread of 300 keV (FWHM) interacted with argon gas contained in a high-pressure cell. The cell was viewed with HPGe detectors placed at 90$^{\mathrm{o}}$ relative to the incident photon beam in the horizontal and vertical planes to distinguish between E1 and M1 de-excitation $\gamma $-rays. Our re-measurement provided an increase in M1 strength by a factor of approximately 3, mostly due to the discovery that the known level in $^{\mathrm{40}}$Ar at 9.84 MeV is of M1 character and not of E1 character, as previously thought. In addition to the already known M1 state at 9.76 MeV [1], we observed weaker M1 states at 9.70, 9.81, 9.87, and 9.89 MeV. [1] T.C. Li \textit{et al}., Phys. Rev. C \textbf{73}, 054306 (2006). [Preview Abstract] |
Thursday, October 26, 2017 9:06AM - 9:18AM |
CH.00004: Dissecting Reactor Antineutrino Flux Calculations E.A. McCutchan, A.A. Sonzogni, M.N. Nino, A.C. Hayes Predictions of the antineutrino flux and spectrum from a nuclear reactor make use of a numerical method to convert experimental aggregate electron spectra into corresponding antineutrino spectra. Based on these predictions, a systematic deficit in the total number of measured antineutrinos (the so-called reactor antineutrino anomaly) and a spectra distortion in the 5-7 MeV region (the so-called bump) has been observed. Recent measurements of the time evolution of the antineutrino flux by the Daya Bay collaboration has suggested that only $^{\mathrm{235}}$U exhibits the anomaly, while $^{\mathrm{239}}$Pu agrees with the current theoretical predictions. In the present work, we perform a quantitative investigation into the assumptions and approximations used in the conversion method. By simultaneously fitting the aggregate electron spectra and the Daya Bay antineutrino spectra, we explore if any correction terms can account for both the anomaly and the bump. Furthermore, we analyze the time evolution flux data from Daya Bay using a revised conversion method. Results from this analysis will be presented. [Preview Abstract] |
Thursday, October 26, 2017 9:18AM - 9:30AM |
CH.00005: PROSPECT: The Precision Reactor Oscillation and Spectrum Experiment Pieter Mumm The PROSPECT short-baseline reactor experiment will perform a precision measurement of the antineutrino spectrum associated with 235-U and probe, to high-significance, sterile neutrino oscillation with mass states in the eV region. PROSPECT will operate at distances of 7-12m in close proximity to the high-flux isotope reactor (HFIR) at ORNL . ~This presents several design challenges, particularly the need for excellent control of background. The PROSPECT detector consists of a 4 ton highly-segmented 6Li-loaded liquid scintillator volume with good in-situ calibration capabilities. Extensive prototyping has shown excellent light collection efficiency, uniformity of response, and background rejection capabilities. We will describe the experimental program, discovery potential, and progress in the construction of PROSPECT. [Preview Abstract] |
Thursday, October 26, 2017 9:30AM - 9:42AM |
CH.00006: Implications of Higgs Universality for neutrinos Gerard Stephenson, T. Goldman Higgs Universality means that the right-chiral Weyl spinors of each charge type couple universally to the Higgs doublet-left-chiral Weyl spinor weak singlets for quarks in the current basis,so the quark mass matrices are of the pairing form. We have shown that the known quark masses and weak current mixing can be recovered by invoking perturbative BSM corrections. The application to the charged leptons is immediate. Assuming the charged fermion-like mass terms for the neutrinos have a similar structure, but that Majorana mass terms for the sterile right-chiral spinors (which qualify as dark matter) must also be included, we show that the ratios of the resulting sterile neutrino masses vary as the square of the ratios of the charged fermion masses. The results are consistent with short-baseline neutrino oscillation experiments. Using that scale, we predict sterile neutrinos at masses of several keV/$c^2$ and some tens of MeV$/c^2$, which may decay to a photon and a lighter neutrino. [Preview Abstract] |
Thursday, October 26, 2017 9:42AM - 9:54AM |
CH.00007: Nucleon Axial-Vector Form Factors from Lattice QCD Huey-Wen Lin We present high-statistics results for the nucleon isovector axial form factors from a $2+1+1$-flavor lattice calculation, including 2 ensembles at physical pion mass and 3 lattice spacings. High-statistics estimates allow us to quantify systematic uncertainties in the extraction of $G_A(Q^2)$ with ${\cal M}_A$ estimated to be $1.39(28)$ GeV, which is close to the value obtained by the miniBooNE collaboration ($1.35(17)$ GeV). If time allows, we will also discuss the partially conserved axial current (PCAC) relation in our calculations. [Preview Abstract] |
Thursday, October 26, 2017 9:54AM - 10:06AM |
CH.00008: On the break down of reality at superluminal velocities, Quantum entanglement and Singularities (Complex Universe) Ahmad Reza Estakhr In the real world nothing can move faster than the speed of light. But what convinces you that our world is all real? I realized that reality break down at superluminal velocities (By studying the physics of tachyonic neutrinos), Quantum entanglement and Singularities of Black Holes, I realized that infact our world is complex and has two parts, one part of the world is real (the part that nothing can move faster than the speed of light) but the other part of the world is imaginary. $z=a+ib$ Einstein was wrong because he thought our world is completely real (Of course he was not alone in this belief، almost all physicists believe that our world is completely real) Eventually his false interpretation of reality censored imaginary part of the universe. Einstein's Second Postulate of special theory of relativity was a misleading guide to the true nature of reality. He 'expected' the true nature of reality will follow to his (false) postulate, But the true nature of reality is unlike what anyone ever 'expected'!. Einstein twist facts to suit his theory of relativity instead of theories to suit facts!. This is a dramatic revisions to our conception of the theory of relativity, Reality is complex but We always perceive its real part. [Preview Abstract] |
Thursday, October 26, 2017 10:06AM - 10:18AM |
CH.00009: \textsuperscript{227}Ac as a Calibration Source in PROSPECT Danielle Berish The Precision Reactor Oscillation and SPECTrum Experiment (PROSPECT) is designed to probe short baseline oscillations of antineutrinos in search of eV-scale sterile neutrinos and precisely measure the \textsuperscript{235}U reactor antineutrino spectrum from the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. The PROSPECT antineutrino detector will provide excellent background rejection and position resolution due to its segmented design and use of \textsuperscript{6}Li-loaded liquid scintillator. Due to characteristics of its decay chain, \textsuperscript{227}Ac has been proposed as a calibration source that would be dissolved evenly throughout the liquid scintillator. We will present results showing the benefits of using a dissolved \textsuperscript{227}Ac source by exploiting the correlated production of alphas from \textsuperscript{219}Rn $\rightarrow$ \textsuperscript{215}Po $\rightarrow$ \textsuperscript{211}Pb in the \textsuperscript{227}Ac decay chain. [Preview Abstract] |
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