R. J. Wilkes
A5023982449- Particle physics theoretical and experimental studies
- Neutrino Physics Research
- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Nuclear physics research studies
- Particle Detector Development and Performance
- Radiation Therapy and Dosimetry
- Muon and positron interactions and applications
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear Physics and Applications
- Particle accelerators and beam dynamics
- Gamma-ray bursts and supernovae
- Nuclear reactor physics and engineering
- Radioactivity and Radon Measurements
- Radioactive Decay and Measurement Techniques
- Superconducting Materials and Applications
- Atomic and Molecular Physics
- Solar and Space Plasma Dynamics
- Stochastic processes and statistical mechanics
- Markov Chains and Monte Carlo Methods
- Computational Physics and Python Applications
University of Washington
2012-2022
Seattle University
2002-2014
Boston University
1991-2013
University of Alberta
2011-2013
Institute of Particle Physics
2011-2013
University of California, Irvine
2013
Chonnam National University
2013
National Centre for Nuclear Research
2011
Tohoku University
1991-2008
Dongshin University
2008
The K2K experiment observes indications of neutrino oscillation: a reduction $\nu_\mu$ flux together with distortion the energy spectrum. Fifty-six beam events are observed in Super-Kamiokande (SK), 250 km from production point, an expectation $80.1^{+6.2}_{-5.4}$. Twenty-nine one ring $\mu$-like used to reconstruct spectrum, which is better matched expected spectrum oscillation than without. probability that at SK explained by statistical fluctuation without less 1%.
Measurements of the cosmic-ray hydrogen and helium spectra at energies from 20 to 800 TeV are presented. The experiments were performed on a series twelve balloon flights, including several long duration Australia South America Antarctic circumpolar flights. No clear evidence is seen for spectral break. Both consistent with power laws over entire energy range, integral indices 1.80 ± 0.04 1.68+ 0.04−0.06 protons helium, respectively. results fully expectations based supernova shock...
Two unusually-high-multiplicity interactions of high-energy heavy nuclei are observed in a balloon-borne emulsion chamber: A Si + Ag Br event (4 TeV/nucleon) and Ca C (100 TeV/nucleon), with 1015 760 charged particles, respectively. The multiplicities rapidity distributions favor the multichain model but not wounded-nucleon superposition model. high average ${P}_{T}$ (550-700 MeV/c) fluctuations events readily understood terms any models.
S+Au interactions at 200A GeV were observed using emulsion chambers, permitting measurement of pseudorapidities in the central region with precision \ensuremath{\sim}0.01 unit. Scaled-factorial-moment analyses are extended to bin sizes smaller than those accessible other fixed-target experimental techniques. For a sample 151 collisions, moments calculated both ``horizontal'' and ``vertical'' analysis While found rise (in log-log plot) decreasing pseudorapidity size...
Pseudorapidity distributions of relativistic singly charged particles in oxygen-induced emulsion interactions at 14.6, 60, and 200 GeV/nucleon are studied. Limiting fragmentation behavior is observed both the target projectile regions for a central as well minimum-bias sample. Comparisons with fritiof model reveal that picture fragmenting strings successfully describes data.Received 15 December 1988DOI:https://doi.org/10.1103/PhysRevLett.62.2801©1989 American Physical Society
view Abstract Citations (76) References (30) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Energy Spectra of Cosmic Rays above 1 TeV per Nucleon Burnett, T. H. ; Dake, S. Derrickson, J. Fountain, W. F. Fuki, M. Gregory, C. Hayashi, Holynski, R. Iwai, Jones, V. Jurak, A. Lord, Miyamura, O. Oda, Ogata, Parnell, Roberts, E. Strausz, Tabuki, Takahashi, Y. Tominaga, Watts, Wefel, P. Wilczynska, B. Wilczynski, Wilkes, Wolter, Wosiek, JACEE Collaboration Direct...
Energy spectra of protons and helium nuclei in the primary cosmic rays were measured above 1 TeV a series balloon flights emulsion chambers. Differential may be represented by power laws indices -2.81\ifmmode\pm\else\textpm\fi{}0.13 -2.83\ifmmode\pm\else\textpm\fi{}0.20 for He, respectively. No index change was observed either species over energy ranges 5-500 2-50 TeV/nucleon He. Intensities consistent with extrapolations previously published data below TeV/nucleon.
We present a search for electron neutrino appearance from accelerator-produced muon neutrinos in the K2K long-baseline experiment. One candidate event is found data corresponding to an exposure of $4.8\ifmmode\times\else\texttimes\fi{}{10}^{19}$ protons on target. The expected background absence oscillations estimated be $2.4\ifmmode\pm\else\textpm\fi{}0.6$ events and dominated by misidentification neutral current ${\ensuremath{\pi}}^{0}$ production. exclude...
Targets consisting of tungsten and chromium powders imbedded in nuclear emulsion were exposed to the 300-GeV proton beam at Fermi National Accelerator Laboratory. For each event found, number minimum-ionizing (shower) tracks ${n}_{s}$ heavily ionizing ${N}_{h}$ determined, production angles shower measured. 39 events, we find $〈{n}_{s}〉=13.8\ifmmode\pm\else\textpm\fi{}1.2$, $〈{N}_{h}〉=7.2\ifmmode\pm\else\textpm\fi{}0.7$,...
The Cosmic Ray Observatory Project (CROP) at University of Nebraska/Lincoln and the Washington Area Large-scale Time coincidence Array (WALTA) Washington/Seattle are among several outreach projects siting cosmic-ray detectors local high schools in cities around North America, to study origins interactions high-energy cosmic rays. In a collaboration between QuarkNet, program based Fermilab, CROP, WALTA, low-cost data acquisition electronics card has been developed collect synchronize from...
The K2K (KEK E362) long-baseline neutrino oscillations experiment requires synchronization of clocks with 100 nsec accuracy at the near and far detector sites Super-Kamiokande, respectively), which are separated by 250 km. Global Positioning System (GPS) provides a means for satisfying this requirement very low cost. In addition to low-resolution time data (day year, hour, minute, second), commercial GPS receivers output 1 pulse per sec (1PPS) signal whose leading edge is synchronized...
Emulsion chambers were used to measure the transverse momenta of photons or ${\ensuremath{\pi}}^{0}$ mesons produced in high-energy (\ensuremath{\ge}1 TeV/amu) cosmic-ray nucleus-nucleus collisions. A group events having large average have been found which apparently exceed expected limiting values. Analysis at early interaction times, order 1 fm/c, indicates that observed momentum increases with both rapidity density and energy density.
The mass, energy, and centrality dependence of rapidity density distributions relativistic, charged particles, produced in heavy-ion interactions the energy range 4A–200A GeV, are investigated. results indicate that show systematic variations, which used to predict for Au+Au Pb+Pb a model-independent way.Received 6 April 1992DOI:https://doi.org/10.1103/PhysRevLett.69.745©1992 American Physical Society
We have performed a series of cosmic-ray electron observations using balloon-borne emulsion chambers since 1968. While we previously reported the results from subsets exposures, final total exposures up to 2001 are presented here. Our successive experiments yielded exposure 8.19 m2 sr day at altitudes 4.0–9.4 g cm−2. The performance was examined by accelerator beam tests and Monte Carlo simulations, on-board calibrations were carried out flight data. In this work, present spectrum in energy...