L. Littenberg
A5023352347- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Dark Matter and Cosmic Phenomena
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Atomic and Subatomic Physics Research
- Superconducting Materials and Applications
- Particle Detector Development and Performance
- Astrophysics and Cosmic Phenomena
- Computational Physics and Python Applications
- Particle Accelerators and Free-Electron Lasers
- Radiation Detection and Scintillator Technologies
- Black Holes and Theoretical Physics
- Muon and positron interactions and applications
- Particle accelerators and beam dynamics
- Medical Imaging Techniques and Applications
- Nuclear physics research studies
- International Science and Diplomacy
- Atomic and Molecular Physics
- Advanced Semiconductor Detectors and Materials
- Cosmology and Gravitation Theories
- Scientific Research and Discoveries
- Advanced Chemical Physics Studies
- Distributed and Parallel Computing Systems
- Advanced Data Storage Technologies
Brookhaven National Laboratory
2014-2024
Osaka University
2002-2017
TRIUMF
2009
University of Northern British Columbia
2009
University of British Columbia
2009
Arizona State University
2009
High Energy Accelerator Research Organization
2009
Virginia Tech
2009
Cornell University
2004
RIKEN BNL Research Center
1996-2002
Experiment E949 at Brookhaven National Laboratory has observed three new events consistent with the decay K+→π+ν¯ν in pion momentum region 140<Pπ<199 MeV/c an exposure of 1.71×1012 stopped kaons estimated total background 0.93±0.17(stat)+0.32−0.24(syst) events. This brings number to seven. Combining this observation previous results, assuming spectrum predicted by standard model, results a branching ratio B(K+→π+ν¯ν)=(1.73+1.15−1.05)×10−10. An interpretation for alternative models...
The status of the research on muon colliders is discussed and plans are outlined for future theoretical experimental studies. Besides continued work parameters a 3-4 0.5 TeV center-of-mass (CoM) energy collider, many studies now concentrating machine near 0.1 that could be factory s-channel production Higgs particles. We discuss various components in such colliders, starting from proton accelerator needed to generate pions heavy-Z target proceeding through phase rotation decay ($\pi \to \mu...
This biennial Review summarizes much of Particle Physics. Using data from previous editions, plus 2205 new measurements 667 papers, we list, evaluate, and average measured properties gauge bosons, leptons, quarks, mesons, baryons. We also summarize searches for hypothetical particles such as Higgs heavy neutrinos, supersymmetric particles. All the particle search limits are listed in Summary Tables. give numerous tables, figures, formulae, reviews topics Standard Model, detectors,...
Three events for the decay K+→π+ν¯ν have been observed in pion momentum region below K+→π+π0 peak, 140<Pπ<199 MeV/c, with an estimated background of 0.93±0.17(stat.)+0.32−0.24(syst.) events. Combining this observation previously reported results yields a branching ratio B(K+→π+ν¯ν)=(1.73+1.15−1.05)×10−10 consistent standard model prediction.Received 18 August 2008DOI:https://doi.org/10.1103/PhysRevLett.101.191802©2008 American Physical Society
Evidence of a heavy neutrino, $\nu_H$, in the $K^+\to\mu^+\nu_H$ decays was sought using E949 experimental data with an exposure $1.70\times 10^{12}$ stopped kaons. With major background from radiative $K^+\to\mu^+\nu_\mu\gamma$ decay understood and suppressed, upper limits (90% C.L.) on neutrino mixing matrix element between muon $|U_{\mu H}|^2$, were set at level $10^{-7}$ to $10^{-9}$ for mass region 175 300 MeV/$c^2$.
An additional event near the upper kinematic limit for K+-->pi(+)nunu; has been observed by experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, branching ratio is B(K+-->pi(+)nunu;)=(1.47(+1.30)(-0.89))x10(-10) based on three events in pion momentum region 211<P<229 MeV/c. At measured central value of ratio, had a signal-to-background 0.9.
Additional evidence for the rare kaon decay K+-->pi+nu(nu) has been found in a new data set with comparable sensitivity to previously reported result. One event was observed pion momentum region examined, 211<P<229 MeV/c, bringing total combined two. Including all taken, backgrounds were estimated contribute 0.15+/-0.05 events. The branching ratio is B(K+-->pi+nu(nu)) = 1.57(+1.75)(-0.82)x10(-10).
A new measurement of the branching ratio R_{e/μ}=Γ(π^{+}→e^{+}ν+π^{+}→e^{+}νγ)/Γ(π^{+}→μ^{+}ν+π^{+}→μ^{+}νγ) resulted in R_{e/μ}^{exp}=[1.2344±0.0023(stat)±0.0019(syst)]×10^{-4}. This is agreement with standard model prediction and improves test electron-muon universality to level 0.1%.
A search for massive neutrinos has been made in the decay $\pi\rightarrow e^+ \nu$. No evidence was found extra peaks positron energy spectrum indicative of pion decays involving ($\pi\rightarrow \nu_h$). Upper limits (90 \% C.L.) on neutrino mixing matrix element $|U_{ei}|^2$ mass region 60--135 MeV/$c^2$ were set, which are %representing an order magnitude improvement over previous results.
In the present work of PIENU experiment, heavy neutrinos were sought in pion decays π+→μ+ν at rest by examining observed muon energy spectrum for extra peaks addition to expected peak a light neutrino. No evidence was observed. Upper limits set on neutrino mixing matrix |Uμi|2 mass region 15.7–33.8 MeV/c2, improving previous results an order magnitude.
An event consistent with the signature expected for rare kaon decay ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ has been observed. In pion momentum region examined, $211<P<230\mathrm{MeV}/c$, backgrounds are estimated to contribute $0.08\ifmmode\pm\else\textpm\fi{}0.03$ events. If is due ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, branching ratio...
Experiment E949 at Brookhaven National Laboratory studied the rare decay \$K^+\to\pi^+\nu\bar{\nu}$ and other processes with an exposure of $1.77\times 10^{12}$ $K^+$'s. The data were analyzed using a blind analysis technique yielding one candidate event estimated background $0.30\pm0.03$ events. Combining this result observation two events by predecessor experiment E787 gave branching ratio ${\calB}(K^+\to\pi^+\nu\bar{\nu})=(1.47^{+1.30}_{-0.89})\times 10^{-10}$, consistent Standard Model...
Evidence of massive neutrinos in the ${\ensuremath{\pi}}^{+}\ensuremath{\rightarrow}{e}^{+}\ensuremath{\nu}$ decay spectrum was sought with background ${\ensuremath{\pi}}^{+}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}\ensuremath{\rightarrow}{e}^{+}$ chain highly suppressed. Upper limits (90% C.L.) on neutrino mixing matrix element $|{U}_{ei}{|}^{2}$ mass region $60--129\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ were set at level ${10}^{\ensuremath{-}8}$.
We report the results of a search for decay ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ in kinematic region with ${\ensuremath{\pi}}^{+}$ momentum $140<P<195\mathrm{MeV}/c$ using data collected by E787 experiment at BNL. No events were observed. When combined our previous this region, one candidate event an expected background $1.22\ifmmode\pm\else\textpm\fi{}0.24$ 90% C.L. upper limit...
We have searched the missing-mass spectrum of reaction $\mathrm{pp}\ensuremath{\rightarrow}{K}^{+}{K}^{+}X$ for a narrow six-quark resonance in mass range 2.0-2.5 ${\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c}}^{2}$. No structure was observed. Upper limits production cross section such state depend upon and vary from 30 to 130 nb.
From a retroactive data analysis, we obtain the first upper bound on \ensuremath{\Vert}\ensuremath{\Delta}L\ensuremath{\Vert}=2 kaon decay ${\mathit{K}}^{+}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$${\mathrm{\ensuremath{\mu}}}^{+}$${\mathrm{\ensuremath{\mu}}}^{+}$: B(${\mathit{K}}^{+}$...
Following a major shortage of 99Mo in the 2009–2010 period, concern grew that aging reactor production facilities needed to be replaced. Most producers were using highly enriched 235U (HEU) as target material. The Organisation for Economic Co-...Read More
Using a proportional-chamber spectrometer and an array of lead-glass photon detectors, we have observed four examples the decay ${{K}_{L}}^{0}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}\ensuremath{\gamma}$, one candidate for ${{K}_{L}}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}\ensuremath{\gamma}$. The corresponding branching ratios are (17.4\ifmmode\pm\else\textpm\fi{}8.7)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}6}$...