A5039459940- Muon and positron interactions and applications
- Particle physics theoretical and experimental studies
- Atomic and Molecular Physics
- Quantum Chromodynamics and Particle Interactions
- Neutrino Physics Research
- Particle Detector Development and Performance
- High-Energy Particle Collisions Research
- Quantum, superfluid, helium dynamics
- Dark Matter and Cosmic Phenomena
- Particle accelerators and beam dynamics
- Nuclear physics research studies
- Cold Fusion and Nuclear Reactions
- Atomic and Subatomic Physics Research
- Advanced Chemical Physics Studies
- Nuclear Physics and Applications
- Chemical Reactions and Isotopes
- Radiation Detection and Scintillator Technologies
- Superconducting Materials and Applications
- Advanced NMR Techniques and Applications
- Scientific Research and Discoveries
- Magnetic confinement fusion research
- X-ray Spectroscopy and Fluorescence Analysis
- Mass Spectrometry Techniques and Applications
- Distributed and Parallel Computing Systems
- Black Holes and Theoretical Physics
University of Washington
2013-2024
California University of Pennsylvania
2024
Paul Scherrer Institute
1989-2015
Petersburg Nuclear Physics Institute
2015
University of Illinois Urbana-Champaign
2003-2015
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati
2015
University of Illinois System
2011-2013
University of California, Berkeley
1998-2011
Campbell Collaboration
2008
Lawrence Berkeley National Laboratory
1991-2007
We present a new measurement of the positive muon magnetic anomaly, a_{μ}≡(g_{μ}-2)/2, from Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. have analyzed more than 4 times number positrons decay our previous result 2018 data. The systematic error is reduced by factor 2 due to better running conditions, stable beam, improved knowledge field weighted distribution, ω[over ˜]_{p}^{'}, anomalous precession frequency corrected for beam dynamics effects, ω_{a}. From ratio...
The Muon g-2 Experiment at Fermi National Accelerator Laboratory (FNAL) has measured the muon anomalous precession frequency $ω_a$ to an uncertainty of 434 parts per billion (ppb), statistical, and 56 ppb, systematic, with data collected in four storage ring configurations during its first physics run 2018. When combined a precision measurement magnetic field experiment's ring, determines anomaly $a_μ({\rm FNAL}) = 116\,592\,040(54) \times 10^{-11}$ (0.46 ppm). This article describes...
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
We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < or =Q2 =1.0 GeV2. These asymmetries, arising from interference electromagnetic and neutral weak interactions, are sensitive to strange-quark contributions currents proton. The measurements were made at Jefferson Laboratory using a toroidal spectrometer detect recoiling protons liquid hydrogen target. results indicate nonzero, Q2 dependent, provide new information...
The Fermi National Accelerator Laboratory has measured the anomalous precession frequency $a^{}_\mu = (g^{}_\mu-2)/2$ of muon to a combined precision 0.46 parts per million with data collected during its first physics run in 2018. This paper documents measurement magnetic field storage ring. is monitored by nuclear resonance systems and calibrated terms equivalent proton spin spherical water sample at 34.7$^\circ$C. weighted distribution resulting $\tilde{\omega}'^{}_p$, denominator ratio...
We present details on a new measurement of the muon magnetic anomaly, $a_\mu = (g_\mu -2)/2$. The result is based positive data taken at Fermilab's Muon Campus during 2019 and 2020 accelerator runs. uses $3.1$ GeV$/c$ polarized muons stored in $7.1$-m-radius storage ring with $1.45$ T uniform field. value $ a_{\mu}$ determined from measured difference between spin precession frequency its cyclotron frequency. This normalized to strength field, using Nuclear Magnetic Resonance (NMR). ratio...
Muon-catalyzed deuterium-tritium fusion was investigated within a wide range of mixtures in liquid and gas (23--35 K) by detection neutrons. Our improved analysis includes hyperfine effects allows clear separation intrinsic dt sticking ${\ensuremath{\omega}}_{s}$ from kinetic effects. Strongly density-dependent cycle rates with values up to 1.45\ifmmode\times\else\texttimes\fi{}${10}^{8}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$, yields 113 fusions per muon,...
We report a measurement of the positive muon lifetime to precision 1.0 ppm; it is most precise particle ever measured. The experiment used time-structured, low-energy beam and segmented plastic scintillator array record more than 2×1012 decays. Two different stopping target configurations were employed in independent data-taking periods. combined results give τμ+(MuLan)=2 196 980.3(2.2) ps, 15 times as any previous experiment. gives value for Fermi constant: GF(MuLan)=1.166 378 8(7)×10−5...
We present a detailed report of the method, setup, analysis and results precision measurement positive muon lifetime. The experiment was conducted at Paul Scherrer Institute using time-structured, nearly 100%-polarized, surface beam segmented, fast-timing, plastic scintillator array. employed two target arrangements; magnetized ferromagnetic with ~4 kG internal magnetic field crystal quartz in 130 G external field. Approximately 1.6 x 10^{12} positrons were accumulated together data yield...
Weak capture in muonic hydrogen ($μ$H) as a probe of the chiral properties and nucleon structure predictions Quantum Chromodynamics (QCD) is reviewed. A recent determination axial-vector charge radius squared, $r_A^2(z\; {\rm exp.}) = 0.46(22)\;{\rm fm}^2$, from model independent $z$ expansion analysis neutrino-nucleon scattering data employed conjunction with MuCap measurement singlet rate, $Λ_{\rm singlet}^{\rm MuCap} 715.6(7.4)\;{\rm s}^{-1}$, to update induced pseudoscalar coupling:...
The rate of nuclear muon capture by the proton has been measured using a new technique based on time projection chamber operating in ultraclean, deuterium-depleted hydrogen gas, which is key to avoiding uncertainties from muonic molecule formation. hyperfine singlet ground state μp atom was obtained difference between μ− disappearance and world average for μ+ decay rate, yielding ΛS=725.0±17.4 s−1, induced pseudoscalar coupling nucleon, gP(q2=−0.88m2μ)=7.3±1.1, extracted.Received 16 April...
The MuCap experiment at the Paul Scherrer Institute has measured rate L_S of muon capture from singlet state muonic hydrogen atom to a precision 1%. A beam was stopped in time projection chamber filled with 10-bar, ultra-pure gas. Cylindrical wire chambers and segmented scintillator barrel detected electrons decay. is determined difference between mu- disappearance free decay rate. result based on analysis 1.2 10^10 decays, which we extract = (714.9 +- 5.4(stat) 5.1(syst)) s^-1 derive...
We present a new measurement of the positive muon magnetic anomaly, $a_\mu \equiv (g_\mu - 2)/2$, from Fermilab Muon $g\!-\!2$ Experiment using data collected in 2019 and 2020. have analyzed more than 4 times number positrons decay our previous result 2018 data. The systematic error is reduced by factor 2 due to better running conditions, stable beam, improved knowledge field weighted distribution, $\tilde{\omega}'^{}_p$, anomalous precession frequency corrected for beam dynamics effects,...
In recent years, the gain suppression mechanism has been studied for large localized charge deposits in Low-Gain Avalanche Detectors (LGADs). LGADs are a thin silicon detector with highly doped layer that provides moderate internal signal amplification. Using CENPA Tandem accelerator at University of Washington, response different thicknesses to MeV-range energy from proton beam were studied. Three LGAD prototypes 50~$\mu$m, 100~$\mu$m, 150~$\mu$m characterized. The devices' was determined...
High rates for mesomolecular processes were found in a study of neutron spectra from muon-catalyzed $\mathrm{dt}$ fusion low-density D/T mixtures. An interpretation is given terms reaction-kinetics model which includes hyperfine effects. The components the $d\ensuremath{\mu}t$ formation rates, first separated this experiment, are large 30 to 300 K. unexpected temperature dependence transition rate between $\ensuremath{\mu}t$ states found.
We present a measurement and partial wave analysis of the final state K L Ϯ ϯ p ¯p annihilation at rest in liquid hydrogen.This reaction is important for study ¯K decay mode scalar resonances, particular, isovectors 0 (980) (1450).The determination (1450) production also fixes coupling isoscalar f (1500) which discussed as glueball.We find B"p →a (1450);a (1450)→K ¯K…ϭ(8.88Ϯ1.68)ϫ10Ϫ4 hence ¯p→ (1500); (1500)→K ¯K…ϭ(4.52Ϯ0.36)ϫ10 Ϫ4 .The mass width are mϭ1480Ϯ30 MeV/c 2 ⌫ϭ265Ϯ15 ,...
This paper reports an experimental investigation of muon-catalyzed fusion in pure deuterium by detection dd neutrons. Target temperatures 25.5--150 K and gas densities 2% 5% liquid-hydrogen density were used. The rates \ensuremath{\lambda}\ifmmode \tilde{}\else \~{}\fi{}F for dd\ensuremath{\mu} formation from both hyperfine states d\ensuremath{\mu} atoms as well the transition \~{}\fi{}FF\ensuremath{'} separated a kinetic analysis observed time spectra. measurement temperature dependence all...
We discovered a strong hyperfine dependence of the resonant formation process $d\ensuremath{\mu}d$ mesomolecules, while detecting neutrons from muon-catalyzed fusion in pure deuterium gas at 34 K. This new effect enabled us to observe directly transitions between states $\ensuremath{\mu}d$ atom for first time and determine an accurate experimental value this transition rate. Our analysis demonstrates importance effects quantitative understanding mechanism formation. Moreover, experiment...
The mean life of the positive muon has been measured to a precision 11 ppm using low-energy, pulsed beam stopped in ferromagnetic target, which was surrounded by scintillator detector array. result, tau(micro)=2.197 013(24) micros, is excellent agreement with previous world average. new average 019(21) micros determines Fermi constant G(F)=1.166 371(6)x10(-5) GeV-2 (5 ppm). Additionally, measurement positive-muon lifetime needed determine nucleon pseudoscalar coupling g(P).