A. W. P. Poon
A5077980042- Neutrino Physics Research
- Particle physics theoretical and experimental studies
- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Atomic and Subatomic Physics Research
- Particle accelerators and beam dynamics
- Muon and positron interactions and applications
- Nuclear Physics and Applications
- Nuclear physics research studies
- Particle Accelerators and Free-Electron Lasers
- Radio Frequency Integrated Circuit Design
- Superconducting Materials and Applications
- Quantum Chromodynamics and Particle Interactions
- Medical Imaging Techniques and Applications
- Microwave Engineering and Waveguides
- Scientific Research and Discoveries
- Superconducting and THz Device Technology
- Scientific Computing and Data Management
- Distributed and Parallel Computing Systems
- X-ray Spectroscopy and Fluorescence Analysis
- Quantum, superfluid, helium dynamics
- Radiation Effects in Electronics
- Research Data Management Practices
Lawrence Berkeley National Laboratory
2016-2025
Campbell Collaboration
2004-2022
Thomas Jefferson National Accelerator Facility
2022
Carnegie Mellon University
2021
Peraso Technologies (Canada)
2014-2020
United States Agency for International Development
2019
University of California, Berkeley
2004-2015
Black Hills State University
2015
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso
2006
University of Washington
2001-2002
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 Sudbury Neutrino Observatory has precisely determined the total active (nu(x)) 8B solar neutrino flux without assumptions about energy dependence of nu(e) survival probability. measurements were made with dissolved NaCl in heavy water to enhance sensitivity and signature for neutral-current interactions. is found be 5.21 +/- 0.27(stat)+/-0.38(syst) x 10(6) cm(-2) s(-1), agreement previous standard models. A global analysis these other reactor results yields Deltam(2)=7.1(+1.2)(-0.6)...
Neutrinoless double-beta decay is a forbidden, lepton-number-violating nuclear transition whose observation would have fundamental implications for neutrino physics, theories beyond the Standard Model and cosmology. In this review, we summarize theoretical progress to understand process, expectations under various particle physics models, as well challenges that affect precise predictions of half-life. We will also provide synopsis current future large-scale experiments aim at discovering...
We report results from a combined analysis of solar neutrino data all phases the Sudbury Neutrino Observatory (SNO). By exploiting particle identification information obtained proportional counters installed during third phase, this improved background rejection in that phase experiment. The SNO resulted total flux active flavors ${}^{8}\mathrm{B}$ decays Sun...
Abstract Since the discovery of neutrino oscillations, we know that neutrinos have non-zero mass. However, absolute neutrino-mass scale remains unknown. Here report upper limits on effective electron anti-neutrino mass, m ν , from second physics run Karlsruhe Tritium Neutrino experiment. In this experiment, is probed via a high-precision measurement tritium β -decay spectrum close to its endpoint. This method independent any cosmological model and does not rely assumptions whether Dirac or...
The M ajorana D emonstrator will search for the neutrinoless double-beta<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mo stretchy="false">(</mml:mo><mml:mi>β</mml:mi><mml:mi>β</mml:mi><mml:mfenced separators="|"><mml:mrow><mml:mn fontstyle="italic">0</mml:mn><mml:mi>ν</mml:mi></mml:mrow></mml:mfenced><mml:mo stretchy="false">)</mml:mo></mml:math>decay of isotope<mml:math id="M2"/>Ge with a mixed array enriched and natural germanium detectors. observation this rare...
The Majorana Collaboration is operating an array of high purity Ge detectors to search for neutrinoless double-β decay in ^{76}Ge. Demonstrator comprises 44.1 kg (29.7 enriched ^{76}Ge) split between two modules contained a low background shield at the Sanford Underground Research Facility Lead, South Dakota. Here we present results from data taken during construction, commissioning, and start full operations. We achieve unprecedented energy resolution 2.5 keV FWHM Q_{ββ} very with no...
Advances in machine learning methods provide tools that have broad applicability scientific research. These techniques are being applied across the diversity of nuclear physics research topics, leading to advances will facilitate discoveries and societal applications. This Review gives a snapshot which has been transformed by techniques.
The Majorana Demonstrator searched for neutrinoless double-β decay (0νββ) of ^{76}Ge using modular arrays high-purity Ge detectors operated in vacuum cryostats a low-background shield. with up to 40.4 kg (27.2 enriched ∼88% ^{76}Ge). From these measurements, the has accumulated 64.5 yr active exposure. With world-leading energy resolution 2.52 keV FWHM at 2039 Q_{ββ} (0.12%), we set half-life limit 0νββ T_{1/2}>8.3×10^{25} (90% C.L.). This provides range upper limits on m_{ββ} (113-269) meV...
That neutrinos carry a nonvanishing rest mass is evidence of physics beyond the Standard Model elementary particles. Their absolute holds relevance in fields from particle to cosmology. We report on search for effective electron antineutrino with KATRIN experiment. performs precision spectroscopy tritium β-decay close kinematic endpoint. On basis first five measurement campaigns, we derived best-fit value <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow>...
Results are reported from a joint analysis of Phase I and II data the Sudbury Neutrino Observatory. The effective electron kinetic energy threshold used is ${T}_{\mathrm{eff}}=3.5$ MeV, lowest yet achieved with water Cherenkov detector data. In units ${10}^{6}$ cm${}^{\ensuremath{-}2}$ ${\mathrm{s}}^{\ensuremath{-}1}$, total flux active-flavor neutrinos $^{8}\mathrm{B}$ decay in Sun measured using neutral current (NC) reaction on deuterons, no constraint neutrino spectrum, found to be...
The Majorana Collaboration is operating an array of high-purity Ge detectors to search for the neutrinoless double-$\ensuremath{\beta}$ decay $^{76}\mathrm{Ge}$. Demonstrator consists 44.1 kg (29.7 enriched 88% in $^{76}\mathrm{Ge}$) split between two modules constructed from ultraclean materials. Both are contained a low-background shield at Sanford Underground Research Facility Lead, South Dakota. We present updated results on $^{76}\mathrm{Ge}$ with $26.0\ifmmode\pm\else\textpm\fi{}0.5$...
Data corresponding to a KamLAND detector exposure of 0.28 kton yr has been used search for nu;(e)'s in the energy range 8.3<E(nu;(e))<14.8 MeV. No candidates were found an expected background 1.1+/-0.4 events. This result can be obtain limit on nu;(e) fluxes any origin. Assuming that all flux its origin Sun and characteristic 8B solar nu(e) spectrum, we upper 3.7 x 10(2) cm(-2) s(-1) (90% C.L.) flux. We interpret this limit, 2.8 10(-4) standard model flux, framework spin-flavor precession...
We present new limits on exotic keV-scale physics based 478 kg d of Majorana Demonstrator commissioning data. Constraints at the 90% confidence level are derived bosonic dark matter (DM) and solar axion couplings, Pauli exclusion principle violating (PEPV) decay, electron decay using monoenergetic peak signal above our background. Our most stringent DM constraints set for 11.8 keV mass particles, limiting g_{Ae}<4.5×10^{-13} pseudoscalars (α^{'}/α)<9.7×10^{-28} vectors. also report a 14.4...
We investigate the sensitivity of tritium β-decay experiments for keV-scale sterile neutrinos. Relic neutrinos in keV mass range can contribute both to cold and warm dark matter content universe. This work shows that a large-scale beta-decay experiment, similar KATRIN experiment is under construction, reach statistical active-sterile neutrino mixing sin2θ ∼ 10−8. The effect uncertainties known theoretical corrections spectrum were investigated, found not affect significantly. It demonstrated...
This review paper provides a summary of the published results Sudbury Neutrino Observatory (SNO) experiment that was carried out by an international scientific collaboration with data collected during period from 1999 to 2006. By using heavy water as detection medium, SNO demonstrated clearly solar electron neutrinos $^8$B decay in core change into other active neutrino flavors transit Earth. The reaction on deuterium has equal sensitivity all also very accurate measure initial flux for...
We report on the data set, handling, and detailed analysis techniques of first neutrino-mass measurement by Karlsruhe Tritium Neutrino (KATRIN) experiment, which probes absolute scale via $\beta$-decay kinematics molecular tritium. The source is highly pure, cryogenic T$_2$ gas. $\beta$ electrons are guided along magnetic field lines toward a high-resolution, integrating spectrometer for energy analysis. A silicon detector counts above threshold spectrometer, so that scan thresholds produces...
We present the results of light sterile neutrino search from second KATRIN measurement campaign in 2019. Approaching nominal activity, $3.76 \times 10^6$ tritium $\beta$-electrons are analyzed an energy window extending down to $40\,$eV below endpoint at $E_0 = 18.57\,$keV. consider $3\nu+1$ framework with three active and one flavor. The analysis is sensitive a fourth mass eigenstate $m_4^2\lesssim1600\,$eV$^2$ active-to-sterile mixing $|U_{e4}|^2 \gtrsim 6 10^{-3}$. As no sterile-neutrino...
We report on the direct search for cosmic relic neutrinos using data acquired during first two science campaigns of KATRIN experiment in 2019. Beta-decay electrons from a high-purity molecular tritium gas source are analyzed by high-resolution MAC-E filter around end point at 18.57 keV. The analysis is sensitive to local neutrino overdensity ratio η<9.7×10^{10}/α (1.1×10^{11}/α) 90% (95%) confidence level with α=1 (0.5) Majorana (Dirac) neutrinos. A fit integrated electron spectrum over...
The fact that neutrinos carry a non-vanishing rest mass is evidence of physics beyond the Standard Model elementary particles. Their absolute bears important relevance from particle to cosmology. In this work, we report on search for effective electron antineutrino with KATRIN experiment. performs precision spectroscopy tritium $\beta$-decay close kinematic endpoint. Based first five neutrino-mass measurement campaigns, derive best-fit value $m_\nu^{2} =...
A fully integrated 802.11ad/WiGig compliant 60 GHz transceiver is presented in a 130 nm SiGe BiCMOS technology. Encompassing an area of 2.3 mm <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\, \times \,$</tex></formula> 2.16 Notation="TeX">$=$</tex></formula> 4.97 xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$^{2}$</tex></formula> , the covers entire band, from 57 to 66 GHz....