2,268 research outputs found

    Search for the Invisible Decay of Neutrons with KamLAND

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    The Kamioka Liquid scintillator Anti-Neutrino Detector is used in a search for single neutron or two-neutron intranuclear disappearance that would produce holes in the s-shell energy level of ^(12)C nuclei. Such holes could be created as a result of nucleon decay into invisible modes (inv), e.g., n→3ν or nn→2ν. The deexcitation of the corresponding daughter nucleus results in a sequence of space and time-correlated events observable in the liquid scintillator detector. We report on new limits for one- and two-neutron disappearance: τ(n→inv) > 5.8 × 10^(29) years and τ(nn→inv) > 1.4 × 10^(30) years at 90% C.L. These results represent an improvement of factors of ~3 and > 10^4 over previous experiments

    Measurement of neutrino oscillation with KamLAND: Evidence of spectral distortion

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    We present results of a study of neutrino oscillation based on a 766 ton/year exposure of KamLAND to reactor antineutrinos. We observe 258 v_e candidate events with energies above 3.4 MeV compared to 365.2±23.7 events expected in the absence of neutrino oscillation. Accounting for 17.8±7.3 expected background events, the statistical significance for reactor v_e over bar (e) disappearance is 99.998%. The observed energy spectrum disagrees with the expected spectral shape in the absence of neutrino oscillation at 99.6% significance and prefers the distortion expected from v_e oscillation effects. A two-neutrino oscillation analysis of the KamLAND data gives Δm^2=7.9_(-0.5)^(+0.6)x10^(-5) eV^2. A global analysis of data from KamLAND and solar-neutrino experiments yields Δm^2=7.9_(-0.5)^(+0.6)x10^(-5) eV^2 and tan^2θ=0.40_(-0.07)^(+0.10), the most precise determination to date

    The Utility of HEGIS Data in Making Institutional Comparisons

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    Several changes need to be made in the instructions to the HEGIS finance form to enhance the usefulness of the information

    The visual nonverbal memory trace is fragile when actively maintained, but endures passively for tens of seconds

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    Despite attempts at active maintenance in the focus of attention, the fragile nature of the visual nonverbal memory trace may be revealed when the retention interval between target memoranda and probed recall on a trial is extended. In contrast, a passively maintained or unattended visual memory trace may be revealed as persisting proactive interference extending across quite extended intervals between trials in a recent probes task. The present study, comprising five experiments, used this task to explore the persistence of such a passive visual memory trace over time. Participants viewed some target visual items (for example, abstract colored patterns) followed by a variable retention interval and a probe item. The task was to report whether the probe matched one of the targets or not. A decaying active memory trace was indicated by poorer performance as the memory retention interval was extended on a trial. However, when the probe was a member of the target set from the preceding trial, task performance was poorer than a comparison novel probe, demonstrating proactive interference. Manipulations of the intertrial interval revealed that the temporal persistence of the passive memory trace of an old target was impressive, and proactive interference was largely resilient to a simple ‘cued forgetting’ manipulation. These data support the proposed two-process memory conception (active–passive memory) contrasting fragile active memory traces decaying over a few seconds with robust passive traces extending to tens of seconds

    Quasiparticle dynamics and spin-orbital texture of the SrTiO3 two-dimensional electron gas

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    Two-dimensional electron gases (2DEGs) in SrTiO3_3 have become model systems for engineering emergent behaviour in complex transition metal oxides. Understanding the collective interactions that enable this, however, has thus far proved elusive. Here we demonstrate that angle-resolved photoemission can directly image the quasiparticle dynamics of the dd-electron subband ladder of this complex-oxide 2DEG. Combined with realistic tight-binding supercell calculations, we uncover how quantum confinement and inversion symmetry breaking collectively tune the delicate interplay of charge, spin, orbital, and lattice degrees of freedom in this system. We reveal how they lead to pronounced orbital ordering, mediate an orbitally-enhanced Rashba splitting with complex subband-dependent spin-orbital textures and markedly change the character of electron-phonon coupling, co-operatively shaping the low-energy electronic structure of the 2DEG. Our results allow for a unified understanding of spectroscopic and transport measurements across different classes of SrTiO3_3-based 2DEGs, and yield new microscopic insights on their functional properties.Comment: 10 pages including supplementary information, 4+4 figure

    Nuclear structure in 95,97Ru nuclei

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    The high-spin level structures of the nuclei 95,97Ru have been studied via the 92Mo(6Li,p2n)95Ru and 93Nb(7Li,3n)97Ru reactions, using γ-γ coincidence, γ-W(θ), and pulsed-beam-γ measurements. Shell-model calculations of energy levels and B(E2) values for 95Ru have been performed and compared with the experimentally observed levels and the measured (21/2)+ and (17/2)+ lifetimes. A collective ΔJ=2 band has been identified with the 1h11/2 neutron state in 97Ru, and discussed in the context of the general nature of collectivity in nuclei outside the N=50 closed shell. No ΔJ=1 band associated with the 1g9/2 neutron-hole intruder state was found in either of the N=51,53 Ru nuclei, as observed previously for the 1g9/2 proton-hole intruder states in the Z=51 Sb and Z=53 I nuclei

    Parity Violation in Elastic Electron-Proton Scattering and the Proton's Strange Magnetic Form Factor

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    We report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A=-4.92 +- 0.61 +- 0.73 ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections.Comment: 4 pages, 3 figures, submitted to Physical Review Letters, Sept 199

    Control of a two-dimensional electron gas on SrTiO3(111) by atomic oxygen

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    We report on the formation of a two-dimensional electron gas (2DEG) at the bare surface of (111) oriented SrTiO3. Angle resolved photoemission experiments reveal highly itinerant carriers with a 6-fold symmetric Fermi surface and strongly anisotropic effective masses. The electronic structure of the 2DEG is in good agreement with self-consistent tight-binding supercell calculations that incorporate a confinement potential due to surface band bending. We further demonstrate that alternate exposure of the surface to ultraviolet light and atomic oxygen allows tuning of the carrier density and the complete suppression of the 2DEG.Comment: 5 pages, 4 figure

    Software-defined networking for ubiquitous healthcare service delivery

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    The growth of the mobile, portable devices and the server-to-server communication through cloud computing increase the network traffic. The dependence of the ubiquitous healthcare service delivery on the network connectivity creates failures that may interrupt or delay the treatment plan with adverse effects in patients’ quality of life even leading to mortality. In the present work, we propose the incorporation of Software Defined Networking (SDN) features in the healthcare domain in order to provide the appropriate bandwidth and guarantee the accurate real time medical data transmission independently of the connectivity of the ISP provider. The SDN controller monitors the network traffic and specifies how traffic should be routed providing load balancing, lower delays and better performance. Finally, the proposed healthcare architecture addresses the SDN scalability challenge by incorporating the logically centralized control plane using multiple distributed controllers. A 2-tier hierarchical overlay is formed among SDN controllers following the principles of peer-to-peer networking

    Conference Summary of QNP2018

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    This report is the summary of the Eighth International Conference on Quarks and Nuclear Physics (QNP2018). Hadron and nuclear physics is the field to investigate high-density quantum many-body systems bound by strong interactions. It is intended to clarify matter generation of universe and properties of quark-hadron many-body systems. The QNP is an international conference which covers a wide range of hadron and nuclear physics, including quark and gluon structure of hadrons, hadron spectroscopy, hadron interactions and nuclear structure, hot and cold dense matter, and experimental facilities. First, I introduce the current status of the hadron and nuclear physics field related to this conference. Next, the organization of the conference is explained, and a brief overview of major recent developments is discussed by selecting topics from discussions at the plenary sessions. They include rapidly-developing field of gravitational waves and nuclear physics, hadron interactions and nuclear structure with strangeness, lattice QCD, hadron spectroscopy, nucleon structure, heavy-ion physics, hadrons in nuclear medium, and experimental facilities of EIC, GSI-FAIR, JLab, J-PARC, Super-KEKB, and others. Nuclear physics is at a fortunate time to push various projects at these facilities. However, we should note that the projects need to be developed together with related studies in other fields such as gravitational physics, astrophysics, condensed-matter physics, particle physics, and fundamental quantum physics.Comment: 10 pages, LaTeX, 1 style file, 3 figure files, Proceedings of Eighth International Conference on Quarks and Nuclear Physics (QNP2018), November 13-17, 2018, Tsukuba, Japa
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