K. Arisaka
A5074789353- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Dark Matter and Cosmic Phenomena
- High-Energy Particle Collisions Research
- Particle Detector Development and Performance
- Neutrino Physics Research
- Astrophysics and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Black Holes and Theoretical Physics
- Computational Physics and Python Applications
- Medical Imaging Techniques and Applications
- Advanced Fluorescence Microscopy Techniques
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Neural dynamics and brain function
- Astronomy and Astrophysical Research
- Visual perception and processing mechanisms
- Atmospheric Ozone and Climate
- Photocathodes and Microchannel Plates
- Muon and positron interactions and applications
University of California, Los Angeles
2011-2025
California NanoSystems Institute
2009-2025
Astronomy and Space
2006-2022
Princeton University
2015
Institute of High Energy Physics
2010-2012
European Organization for Nuclear Research
2012
University of California, San Diego
2012
UCLA Health
2009
Pierre Auger Observatory
2007
Universidade Federal Fluminense
2007
We report on a search for particle dark matter with the XENON100 experiment, operated at Laboratori Nazionali del Gran Sasso 13 months during 2011 and 2012. features an ultralow electromagnetic background of (5.3 ± 0.6) × 10(-3) events/(keV(ee) kg day) in energy region interest. A blind analysis 224.6 live days 34 exposure has yielded no evidence interactions. The two candidate events observed predefined nuclear recoil range 6.6-30.5 keV(nr) are consistent expectation (1.0 0.2) events....
We present results from the direct search for dark matter with XENON100 detector, installed underground at Laboratori Nazionali del Gran Sasso of INFN, Italy. is a two-phase time projection chamber 62 kg liquid xenon target. Interaction vertex reconstruction in three dimensions millimeter precision allows to select only innermost 48 as ultra-low background fiducial In 100.9 live days data, acquired between January and June 2010, no evidence found. Three candidate events were observed...
Using data collected at the Pierre Auger Observatory during past 3.7 years, we demonstrated a correlation between arrival directions of cosmic rays with energy above 6 × 10 19 electron volts and positions active galactic nuclei (AGN) lying within ∼75 megaparsecs. We rejected hypothesis an isotropic distribution these least 99% confidence level from prescribed priori test. The observed is compatible that highest-energy particles originate nearby extragalactic sources whose flux has not been...
The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world's largest cosmic ray observatory. objectives of Observatory are to probe origin and characteristics rays above $10^{17}$ eV study interactions these, most energetic particles observed nature. design features an array 1660 water-Cherenkov particle detector stations spread over 3000 km$^2$ overlooked by 24 air fluorescence telescopes. In addition, three elevation telescopes overlook 23.5 km$^2$,...
The energy spectrum of cosmic rays above 2.5 x 10;{18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. spectral index gamma particle flux, J proportional, variantE;{-gamma}, energies between 4 eV and 10;{19} 2.69+/-0.02(stat)+/-0.06(syst), steepening to 4.2+/-0.4(stat)+/-0.06(syst) higher energies. hypothesis a single power law rejected with significance greater than 6 standard deviations. data are consistent prediction by Greisen Zatsepin Kuz'min.
We describe the measurement of depth maximum, X{max}, longitudinal development air showers induced by cosmic rays. Almost 4000 events above 10;{18} eV observed fluorescence detector Pierre Auger Observatory in coincidence with at least one surface station are selected for analysis. The average shower maximum was found to evolve energy a rate (106{-21}{+35}) g/cm{2}/decade below 10{18.24+/-0.05} eV, and (24+/-3) this energy. measured shower-to-shower fluctuations decrease from about 55 26...
The XENON100 experiment, in operation at the Laboratori Nazionali del Gran Sasso Italy, is designed to search for dark matter WIMPs scattering off 62 kg of liquid xenon an ultra-low background dual-phase time projection chamber. In this letter, we present first results from analysis 11.17 live days non-blind data, acquired October and November 2009. selected fiducial target 40 kg, within pre-defined signal region, observe no events hence exclude spin-independent WIMP-nucleon elastic...
We present new experimental constraints on the elastic, spin-dependent WIMP-nucleon cross section using recent data from XENON100 experiment, operated in Laboratori Nazionali del Gran Sasso Italy. An analysis of 224.6 live days×34 kg exposure acquired during 2011 and 2012 revealed no excess signal due to axial-vector WIMP interactions with 129Xe 131Xe nuclei. This leads most stringent upper limits WIMP-neutron sections for masses above 6 GeV/c², a minimum 3.5×10(-40) cm² at mass 45 90%...
We report the first results of DarkSide-50, a direct search for dark matter operating in underground Laboratori Nazionali del Gran Sasso (LNGS) and searching rare nuclear recoils possibly induced by weakly interacting massive particles (WIMPs). The detector is Liquid Argon Time Projection Chamber with (46.4+-0.7) kg active mass, operated inside 30 t organic liquid scintillator neutron veto, which turn installed at center 1 kt water Cherenkov veto residual flux cosmic rays. here null...
We have compared the decay rates of ${K}_{L}$ and ${K}_{S}$ to ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ ${\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$ final states using a subset data from KTeV experiment (E832) at Fermilab. find that direct-CP-violation parameter $\mathrm{Re}({\ensuremath{\epsilon}}^{\ensuremath{'}}/\ensuremath{\epsilon})$ is equal...
The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth's crust. Tau leptons from ${\ensuremath{\nu}}_{\ensuremath{\tau}}$ charged-current interactions can emerge and decay atmosphere produce a nearly horizontal shower with significant electromagnetic component. data collected between 1 January 2004 31 August 2007 are used place an upper limit on diffuse flux at EeV energies. Assuming...
Liquid argon is a bright scintillator with potent particle identification properties, making it an attractive target for direct-detection dark matter searches. The DarkSide-50 search here reports the first WIMP results obtained using of low-radioactivity argon. detector, two-phase liquid time projection chamber, located at Laboratori Nazionali del Gran Sasso. underground shown to contain Ar-39 level reduced by factor (1.4 +- 0.2) x 10^3 relative atmospheric We report background-free null...
We present the first results of searches for axions and axion-like-particles with XENON100 experiment. The axion-electron coupling constant, $g_{Ae}$, has been probed by exploiting axio-electric effect in liquid xenon. A profile likelihood analysis 224.6 live days $\times$ 34 kg exposure shown no evidence a signal. By rejecting larger than $7.7 \times 10^{-12}$ (90\% CL) solar axion search, we set best limit to date on this coupling. In frame DFSZ KSVZ models, exclude QCD heavier 0.3...
Many experiments that aim at the direct detection of Dark Matter are able to distinguish a dominant background from expected feeble signals, based on some measured discrimination parameter. We develop statistical model for such using Profile Likelihood ratio as test statistic in frequentist approach. take data calibrations control measurements signal and background, method allows inclusion Monte Carlo simulations. Systematic detector uncertainties, uncertainties energy scale, well...