A5110582661- Particle physics theoretical and experimental studies
- Neutrino Physics Research
- Quantum Chromodynamics and Particle Interactions
- Dark Matter and Cosmic Phenomena
- High-Energy Particle Collisions Research
- Astrophysics and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Mechanical and Optical Resonators
- Nuclear Physics and Applications
- Quantum, superfluid, helium dynamics
- Orbital Angular Momentum in Optics
- Advanced MEMS and NEMS Technologies
- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Computational Physics and Python Applications
- Cosmology and Gravitation Theories
- Advanced Fiber Optic Sensors
- Experimental and Theoretical Physics Studies
- Nuclear physics research studies
- Photonic and Optical Devices
- Superconducting Materials and Applications
- Semiconductor Lasers and Optical Devices
- Muon and positron interactions and applications
Stanford University
2015-2024
Institute of High Energy Physics
2017-2021
Chinese Academy of Sciences
2020-2021
Friedrich-Alexander-Universität Erlangen-Nürnberg
2019
The University of Tokyo
2014
Tohoku University
2014
Kavli Institute for the Physics and Mathematics of the Universe
2014
Colorado State University
2014
University of Bern
2011
Regis University
2008
KamLAND has measured the flux of nu;(e)'s from distant nuclear reactors. We find fewer nu;(e) events than expected standard assumptions about propagation at 99.95% C.L. In a 162 ton.yr exposure ratio observed inverse beta-decay to number without disappearance is 0.611+/-0.085(stat)+/-0.041(syst) for energies >3.4 MeV. context two-flavor neutrino oscillations with CPT invariance, all solutions solar problem except "large mixing angle" region are excluded.
We present results of a study neutrino oscillation based on 766 ton-year exposure KamLAND to reactor anti-neutrinos. observe 258 \nuebar\ candidate events with energies above 3.4 MeV compared 365.2 expected in the absence oscillation. Accounting for 17.8 background events, statistical significance \nuebar disappearance is 99.998%. The observed energy spectrum disagrees spectral shape at 99.6% and prefers distortion from effects. A two-neutrino analysis data gives \DeltaMSq =...
The KamLAND experiment has determined a precise value for the neutrino oscillation parameter Deltam21(2) and stringent constraints on theta12. exposure to nuclear reactor antineutrinos is increased almost fourfold over previous results 2.44 x 10(32) proton yr due longer livetime an enlarged fiducial volume. An undistorted nu[over]e energy spectrum now rejected at >5sigma. Analysis of above inverse beta decay threshold, including geoneutrinos, gives best fit...
We report on a search for neutrinoless double-beta decay of $^{136}$Xe with EXO-200. No signal is observed an exposure 32.5 kg-yr, background ~1.5 x 10^{-3} /(kg yr keV) in the $\pm 1\sigma$ region interest. This sets lower limit half-life $T_{1/2}^{0\nu\beta\beta}$($^{136}$Xe) > 1.6 10$^{25}$ (90% CL), corresponding to effective Majorana masses less than 140-380 meV, depending matrix element calculation.
We present new constraints on the neutrino oscillation parameters $/textyen Delta m^{2}_{21}$, theta_{12}$, and theta_{13}$ from a three-flavor analysis of solar KamLAND data. The data set includes acquired following radiopurity upgrade amounts to total exposure $3.49 \textyen times 10^{32}$ target-proton-year. Under assumption {\textyen it CPT} invariance, two-flavor (/textyen mbox{$\textyen theta_{13} = 0$}) yields best-fit values $\textyen tan^{2} theta_{12} 0.444^{+0.036}_{-0.030}$...
A search for neutrinoless double-beta decay ($0\nu\beta\beta$) in $^{136}$Xe is performed with the full EXO-200 dataset using a deep neural network to discriminate between $0\nu\beta\beta$ and background events. Relative previous analyses, signal detection efficiency has been raised from 80.8% 96.4$\pm$3.0% energy resolution of detector at Q-value improved $\sigma/E=1.23\%$ $1.15\pm0.02\%$ upgraded detector. Accounting new data, median 90% confidence level half-life sensitivity this analysis...
Results from a search for neutrinoless double-beta decay (0νββ) of ^{136}Xe are presented using the first year data taken with upgraded EXO-200 detector. Relative to previous searches by EXO-200, energy resolution detector has been improved σ/E=1.23%, electric field in drift region raised 50%, and system suppress radon volume between cryostat lead shielding implemented. In addition, analysis techniques that improve topological discrimination 0νββ background events have developed....
The ${\overline{\ensuremath{\nu}}}_{e}$ flux and spectrum have been measured at a distance of about 800 m from the reactors Palo Verde Nuclear Generating Station using segmented Gd-loaded liquid scintillator detector. Correlated positron-neutron events reaction ${\overline{\ensuremath{\nu}}}_{e}\stackrel{\ensuremath{\rightarrow}}{p}{e}^{+}n$ were recorded for period 200 d including 55 with one three off refueling. Backgrounds accounted by making use reactor-on reactor-off cycles, also novel...
The analysis and results are presented from the complete data set recorded at Palo Verde between September 1998 July 2000. In experiment, ${\overline{\ensuremath{\nu}}}_{\mathrm{e}}$ interaction rate has been measured a distance of 750 890 m reactors Nuclear Generating Station for total 350 days, including 108 days with one three off refueling. Backgrounds were determined by (a) $\mathrm{swap}$ technique based on difference signal background under reversal positron neutron parts correlated...
We report on the initial results from a measurement of antineutrino flux and spectrum at distance about 800 m three reactors Palo Verde Nuclear Generating Station using segmented gadolinium-loaded scintillation detector. find that agrees with predicted in absence oscillations excluding 90% C.L. nu;(e)-nu;(x) Deltam(2)>1.12x10(-3) eV(2) for maximal mixing sin (2)2straight theta>0.21 large Deltam(2). Our support conclusion atmospheric neutrino observed by Super-Kamiokande do not involve nu(e).
We report the observation of two-neutrino double-beta decay in Xe-136 with T_1/2 = 2.11 +- 0.04 (stat.) 0.21 (sys.) x 10^21 yr. This second order process, predicted by Standard Model, has been observed for several nuclei but not Xe-136. The rate provides new input to matrix element calculations and search more interesting neutrino-less decay, most sensitive probe existence Majorana particles measurement neutrino mass scale.
We report on an improved measurement of the $2\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ half-life ${}^{136}$Xe performed by EXO-200. The use a large and homogeneous time-projection chamber allows for precise estimate fiducial mass used measurement, resulting in small systematic uncertainty. also discuss detail data-analysis methods double-$\ensuremath{\beta}$ decay searches with EXO-200, while emphasizing those directly related to present measurement. is found be...
We report results from a search for stable particles with charge ≳10−5e in bulk matter using levitated dielectric microspheres high vacuum. No evidence such was found total sample of 1.4 ng, providing an upper limit on the abundance per nucleon 2.5×10−14 at 95% confidence level material tested. These provide first direct single ≲0.1e bound macroscopic quantities and demonstrate ability to perform sensitive force measurements optically vacuum.Received 20 August...
We present the results of a search for unknown interactions that couple to mass between an optically levitated microsphere and gold-coated silicon cantilever. The scale geometry apparatus enable new forces appear at distances below $100\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ which would have evaded previous searches due screening mechanisms. data are consistent with electrostatic backgrounds place upper limits on strength $<0.1\text{ }\mathrm{fN}$ in tested. For specific example...
EXO-200 is an experiment designed to search for double beta decay of $^{136}$Xe with a single-phase, liquid xenon detector. It uses active mass 110 kg enriched 80.6% in the isotope 136 ultra-low background time projection chamber capable simultaneous detection ionization and scintillation. This paper describes detector particular attention most innovative aspects design that revolve around reduction backgrounds, efficient use expensive isotopically xenon, optimization energy resolution...
We present the results of a search for extraterrestrial electron antineutrinos ('s) in energy range using KamLAND detector. In an exposure 4.53 kton-year, we identify 25 candidate events. All events can be attributed to background, most importantly neutral current atmospheric neutrino interactions, setting upper limit on probability 8B solar νe's converting into 's at 5.3 × 10−5 (90% CL), if assume undistorted shape. This corresponds flux 93 cm−2 s−1 or event rate 1.6 (kton − year)−1 above...
The next-generation Enriched Xenon Observatory (nEXO) is a proposed experiment to search for neutrinoless double beta ($0\nu\beta\beta$) decay in $^{136}$Xe with target half-life sensitivity of approximately $10^{28}$ years using $5\times10^3$ kg isotopically enriched liquid-xenon time projection chamber. This improvement two orders magnitude over current limits obtained by significant increase the mass, monolithic and homogeneous configuration active medium, multi-parameter measurements...
Abstract The nEXO neutrinoless double beta (0 νββ ) decay experiment is designed to use a time projection chamber and 5000 kg of isotopically enriched liquid xenon search for the in 136 Xe. Progress detector design, paired with higher fidelity its simulation an advanced data analysis, based on one used final results EXO-200, produce sensitivity prediction that exceeds half-life 10 28 years. Specifically, improvements have been made understanding production scintillation photons charge as...
The projected performance and detector configuration of nEXO are described in this pre-Conceptual Design Report (pCDR). is a tonne-scale neutrinoless double beta ($0νββ$) decay search $^{136}$Xe, based on the ultra-low background liquid xenon technology validated by EXO-200. With $\simeq$ 5000 kg enriched to 90% isotope 136, has half-life sensitivity approximately $10^{28}$ years. This represents an improvement about two orders magnitude with respect current results. Based experience gained...
The status of neutrino oscillation searches employing nuclear reactors as sources is reviewed. This technique, a direct continuation the experiments that proved existence neutrinos, today an essential tool in investigating indications oscillations found studying neutrinos produced sun and earth's atmosphere. low energy reactor ${\overline{\ensuremath{\nu}}}_{e}$ makes them ideal for exploring with small mass differences relatively large mixing angles. In last several years determination...
We have measured the mass of Z boson to be 91.14±0.12 GeV/c2, and its width 2.42+0.45−0.35 GeV. If we constrain visible standard-model value, find partial invisible decay modes 0.46±0.10 GeV, corresponding 2.8±0.6 neutrino species, with a 95%-confidence-level upper limit 3.9.Received 12 October 1989DOI:https://doi.org/10.1103/PhysRevLett.63.2173©1989 American Physical Society
We have measured the mass of Z boson to be 91.11±0.23 GeV/c2, and its width 1.61+0.60−0.43 GeV. If we constrain visible standard-model value, find partial invisible decay modes 0.62±0.23 GeV, corresponding 3.8±1.4 neutrino species.Received 24 July 1989DOI:https://doi.org/10.1103/PhysRevLett.63.724©1989 American Physical Society