KamLAND has measured the flux of nu;(e)'s from distant nuclear reactors. We find fewer nu;(e) events than expected from standard assumptions about nu;(e) propagation at the 99.95% C.L. In a 162 ton.yr exposure the ratio of the observed inverse beta-decay events to the expected number without nu;(e) disappearance is 0.611+/-0.085(stat)+/-0.041(syst) for nu;(e) energies >3.4 MeV. In the context of two-flavor neutrino oscillations with CPT invariance, all solutions to the solar neutrino problem except for the "large mixing angle" region are excluded.

First Results from KamLAND: Evidence for Reactor Anti-Neutrino Disappearance

Collective electronic excitations at metal surfaces are well known to play a key role in a wide spectrum of science, ranging from physics and materials science to biology. Here we focus on a theoretical description of the many-body dynamical electronic response of solids, which underlines the existence of various collective electronic excitations at metal surfaces, such as the conventional surface plasmon, multipole plasmons and the recently predicted acoustic surface plasmon. We also review existing calculations, experimental measurements and applications.

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Theory of surface plasmons and surface-plasmon polaritons

We give an $S$-matrix-theoretic demonstration that if the Higgs-boson mass exceeds ${M}_{c}={(8\ensuremath{\pi}\frac{\sqrt{2}}{3}{G}_{F})}^{\frac{1}{2}}$, parital-wave unitarity is not respected by the tree diagrams for two-body scattering of gauge bosons, and the weak interactions must become strong at high energies. We exhibit the relation of this bound to the structure of the Higgs-Goldstone Lagrangian, and speculate on the consequences of strongly coupled Higgs-Goldstone systems. Prospects for the observation of massive Higgs scalars are noted.

Weak interactions at very high energies: The role of the Higgs-boson mass

The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose underground liquid scintillator detector, was proposed with the determination of the neutrino mass hierarchy (MH) as a primary physics goal. The excellent energy resolution and the large fiducial volume anticipated for the JUNO detector offer exciting opportunities for addressing many important topics in neutrino and astro-particle physics. In this document, we present the physics motivations and the anticipated performance of the JUNO detector for various proposed measurements. Following an introduction summarizing the current status and open issues in neutrino physics, we discuss how the detection of antineutrinos generated by a cluster of nuclear power plants allows the determination of the neutrino MH at a 3–4σ significance with six years of running of JUNO. The measurement of antineutrino spectrum with excellent energy resolution will also lead to the precise determination of the neutrino oscillation parameters ${\mathrm{sin}}^{2}{\theta }_{12}$, ${\rm{\Delta }}{m}_{21}^{2}$, and $| {\rm{\Delta }}{m}_{{ee}}^{2}| $ to an accuracy of better than 1%, which will play a crucial role in the future unitarity test of the MNSP matrix. The JUNO detector is capable of observing not only antineutrinos from the power plants, but also neutrinos/antineutrinos from terrestrial and extra-terrestrial sources, including supernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos, atmospheric neutrinos, and solar neutrinos. As a result of JUNO's large size, excellent energy resolution, and vertex reconstruction capability, interesting new data on these topics can be collected. For example, a neutrino burst from a typical core-collapse supernova at a distance of 10 kpc would lead to ∼5000 inverse-beta-decay events and ∼2000 all-flavor neutrino–proton ES events in JUNO, which are of crucial importance for understanding the mechanism of supernova explosion and for exploring novel phenomena such as collective neutrino oscillations. Detection of neutrinos from all past core-collapse supernova explosions in the visible universe with JUNO would further provide valuable information on the cosmic star-formation rate and the average core-collapse neutrino energy spectrum. Antineutrinos originating from the radioactive decay of uranium and thorium in the Earth can be detected in JUNO with a rate of ∼400 events per year, significantly improving the statistics of existing geoneutrino event samples. Atmospheric neutrino events collected in JUNO can provide independent inputs for determining the MH and the octant of the ${\theta }_{23}$ mixing angle. Detection of the (7)Be and (8)B solar neutrino events at JUNO would shed new light on the solar metallicity problem and examine the transition region between the vacuum and matter dominated neutrino oscillations. Regarding light sterile neutrino topics, sterile neutrinos with ${10}^{-5}\,{{\rm{eV}}}^{2}\lt {\rm{\Delta }}{m}_{41}^{2}\lt {10}^{-2}\,{{\rm{eV}}}^{2}$ and a sufficiently large mixing angle ${\theta }_{14}$ could be identified through a precise measurement of the reactor antineutrino energy spectrum. Meanwhile, JUNO can also provide us excellent opportunities to test the eV-scale sterile neutrino hypothesis, using either the radioactive neutrino sources or a cyclotron-produced neutrino beam. The JUNO detector is also sensitive to several other beyondthe-standard-model physics. Examples include the search for proton decay via the $p\to {K}^{+}+\bar{\nu }$ decay channel, search for neutrinos resulting from dark-matter annihilation in the Sun, search for violation of Lorentz invariance via the sidereal modulation of the reactor neutrino event rate, and search for the effects of non-standard interactions. The proposed construction of the JUNO detector will provide a unique facility to address many outstanding crucial questions in particle and astrophysics in a timely and cost-effective fashion. It holds the great potential for further advancing our quest to understanding the fundamental properties of neutrinos, one of the building blocks of our Universe.

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Neutrino Physics with JUNO

The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose underground liquid scintillator detector, was proposed with the determination of the neutrino mass hierarchy as a primary physics goal. It is also capable of observing neutrinos from terrestrial and extra-terrestrial sources, including supernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos, atmospheric neutrinos, solar neutrinos, as well as exotic searches such as nucleon decays, dark matter, sterile neutrinos, etc. We present the physics motivations and the anticipated performance of the JUNO detector for various proposed measurements. By detecting reactor antineutrinos from two power plants at 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4 sigma significance with six years of running. The measurement of antineutrino spectrum will also lead to the precise determination of three out of the six oscillation parameters to an accuracy of better than 1\%. Neutrino burst from a typical core-collapse supernova at 10 kpc would lead to ~5000 inverse-beta-decay events and ~2000 all-flavor neutrino-proton elastic scattering events in JUNO. Detection of DSNB would provide valuable information on the cosmic star-formation rate and the average core-collapsed neutrino energy spectrum. Geo-neutrinos can be detected in JUNO with a rate of ~400 events per year, significantly improving the statistics of existing geoneutrino samples. The JUNO detector is sensitive to several exotic searches, e.g. proton decay via the $p\to K^++\bar\nu$ decay channel. The JUNO detector will provide a unique facility to address many outstanding crucial questions in particle and astrophysics. It holds the great potential for further advancing our quest to understanding the fundamental properties of neutrinos, one of the building blocks of our Universe.

Consequences of neutrino production of M 0 heavy leptons

Algebraic search for candidate preon models

We are in the middle of a time of exciting discovery, namely that neutrinos have mass and oscillate. In order to take the next steps to understand this potential window onto what well might be the mechanism that links the quarks and leptons, we need both new neutrino beams and new detectors. The new beamlines can and should also provide new laboratories for doing charged lepton flavor physics, and the new detectors can and should also provide laboratories for doing other physics like proton decay, supernovae searches, etc. The new neutrino beams serve as milestones along the way to a muon collider, which can answer questions in yet another sector of particle physics, namely the Higgs sector or ultimately the energy frontier. In this report we discuss the current status of neutrino oscillation physics, what other oscillation measurements are needed to fully explore the phenomenon, and finally, what other new physics can be explored as a result of building of these facilities.

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E1 Working Group summary: Neutrino factories and muon colliders : Neutrino Factories and Muon Colliders

We carry out a comparative analysis of three tests for the purpose of observing /sup( /nu-bar)/sup //sub tau/ in a beam-dump experiment. The main source of /sup( /nu-bar)/sup //sub tau/'s is determined to be the hadronic production of F mesons, followed by the decay F /sup + -/ ..-->.. tau/sup + -//sup( /nu-bar)/sup //sub tau/. Possible signatures for various /sup( /nu-bar)/sup //sub tau/-induced processes, together with their corresponding backgrounds, are examined. The muon-trigger test proposed earlier is found to be by far the most promising method. This test identifies /sup( /nu-bar)/sup //sub tau/ events by the muonic decay mode of the tau/sup + -/ produced in /sup( /nu-bar)/sup //sub tau/ charged-current interactions, together with the requirements of substantial missing transverse momentum and distinctive behavior of certain azimuthal-angle distributions describing the emission of the muon, hadron shower, and direction of missing transverse momentum. It can be applied on an event-by-event basis, can separate ..nu../sub tau/- and nu-bar/sub tau/-induced reactions, and is specific to /sup( /nu-bar)/sup //sub tau/. One should be able to use the test to determine directly whether ..nu../sub tau/ is, indeed, a new, sequential neutrino. The test relies on the ability of recently developed neutrino detectors to measure themore » direction of the hadron shower. In addition to this muon-trigger test, we study the possibility of using two others, one based on the identification of events with two hadron showers, due to the semileptonic decay of the produced tau, and the other based on the apparent neutral-to-charged-current event ratio. We find that neither of these two other tests seems feasible. However, it is expected that the muon-trigger test can be used in the near future to observe, for the first time, ..nu../sub tau/ and nu-bar/sub tau/.« less

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Carl H. Albright

Papers

Consequences of neutrino production of M 0 heavy leptons

Algebraic search for candidate preon models

E1 Working Group summary: Neutrino factories and muon colliders : Neutrino Factories and Muon Colliders

Tests for observing ν τ interactions in a beam-dump experiment

How to extract heavy quark and heavy lepton signals in neutrino-induced dilepton events