A5013241826- Atomic and Subatomic Physics Research
- Particle physics theoretical and experimental studies
- Quantum, superfluid, helium dynamics
- Dark Matter and Cosmic Phenomena
- Superconducting Materials and Applications
- Quantum Chromodynamics and Particle Interactions
- Cold Atom Physics and Bose-Einstein Condensates
- Neutrino Physics Research
- Nuclear physics research studies
- Magnetic confinement fusion research
- Particle Accelerators and Free-Electron Lasers
- Advanced Frequency and Time Standards
- Atomic and Molecular Physics
- Advanced NMR Techniques and Applications
- Particle Detector Development and Performance
- High-Energy Particle Collisions Research
- Muon and positron interactions and applications
- NMR spectroscopy and applications
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Scientific Research and Discoveries
- Nuclear Physics and Applications
- Geomagnetism and Paleomagnetism Studies
- Tribology and Lubrication Engineering
- Adhesion, Friction, and Surface Interactions
Argonne National Laboratory
2016-2024
University of Kentucky
2021-2023
University of Washington
2012-2022
Shanghai Jiao Tong University
2010
Southwestern Institute of Physics
2005-2006
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...
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...
A neutron $\ensuremath{\beta}$-decay asymmetry measurement using polarized ultracold neutrons (UCN) determines the correlation between spin of and momentum decay electron. The authors extract ratio weak axial-vector to vector couplings with reduced uncertainties. This new result from first this UCN contributes a benchmark for lattice QCD calculations possibility improved precision on CKM matrix element ${V}_{u\phantom{\rule{0}{0ex}}d}$ $\ensuremath{\beta}$ decay.
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...
A new measurement of the neutron $β$-decay asymmetry $A_0$ has been carried out by UCNA collaboration using polarized ultracold neutrons (UCN) from solid deuterium UCN source at Los Alamos Neutron Science Center (LANSCE). Improvements in experiment have led to reductions both statistical and systematic uncertainties leading $A_0 = -0.11954(55)_{\rm stat.}(98)_{\rm syst.}$, corresponding ratio axial-vector vector coupling $λ\equiv g_A/g_V -1.2756(30)$.
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,...
It has been proposed recently that a previously unobserved neutron decay branch to dark matter particle ($\ensuremath{\chi}$) could account for the discrepancy in lifetime observed experiments use two different measurement techniques. One of possible final states discussed includes single $\ensuremath{\chi}$ along with an ${e}^{+}{e}^{\ensuremath{-}}$ pair. We data from UCNA (Ultracold Neutron Asymmetry) experiment set limits on this channel. Coincident electron-like events are detected...
The Ultracold Neutron Asymmetry (UCNA) experiment was designed to measure the $\beta$-decay asymmetry parameter, $A_0$, for free neutron decay. In experiment, polarized ultracold neutrons are transported into a decay trap, and their electrons detected with $\approx 4\pi$ acceptance two detector packages which provide position energy reconstruction. also has sensitivity $b_{n}$, Fierz interference term in rate. this work, we determine $b_{n}$ from dependence of $A_0$ using data taken during...
The limits on time-reversal invariant tensor-type weak currents from nuclear and neutron $\beta$ decays are evaluated including most recent experimental data. We find that $ -0.14 \times 10^{-2} < (C_T + C^\prime_T)/C_A 1.4 -0.16 - 0.16$ (90% C.L.), while for the case $C_T = C^\prime_T$ | C_T/C_A 3.7 10^{-3} $. These shown to be more stringent than those measurements of radiative pion decay. In addition, sensitivity future $10^{-3}$-level correlation is investigated.
Precision measurements of free-neutron β decay have been used to precisely constrain our understanding the weak interaction. However, neutron Fierz interference term bn, which is particularly sensitive beyond-standard-model tensor currents at TeV scale, has thus far eluded measurement. Here we report first direct constraints on this term, finding bn=0.067±0.005stat+0.090−0.061sys, consistent with standard model. The uncertainty dominated by absolute energy reconstruction and linearity...
Studies of 6He beta decay along with tritium can play an important role in testing ab initio nuclear wave-function calculations and may allow for fixing low-energy constants effective-field theories. Here, we present improved determination the half-life to a relative precision 3×10(-4). Our value 806.89±0.11(stat)(-0.19syst)(+0.23) ms resolves major discrepancy between previous measurements. Calculating statistical rate function determined ft be 803.04(-0.23)(+0.26) s. The extracted...
We report the first precise measurement of a $\ensuremath{\beta}$-recoil correlation from radioactive noble gas ($^{6}\mathrm{He}$) confined via magneto-optical trap. The is motivated by search for exotic tensor-type contributions to charged weak current. Interpreted as tensor currents with right-handed neutrinos, measurements yield $|{C}_{T}/{C}_{A}{|}^{2}\ensuremath{\le}0.022$ (90% confidence limit, C.L.). On other hand, left-handed neutrinos limits are $0.007<{C}_{T}/{C}_{A}<0.111$...
Background: The $\ensuremath{\beta}$ decays of ${}^{3}$H and ${}^{6}$He can play an important role in testing nuclear wave-function calculations fixing low-energy constants effective-field theory approaches. However, there exists a large discrepancy between previous measurements the half-life.Purpose: Our measurement aims at resolving this long-standing half-life providing reliable $ft$ value Gamow-Teller matrix element for comparison with theoretical ab initio calculations.Method: We...
The Muon g−2 experiment at Fermilab (E989) aims to measure the anomalous magnetic moment, aμ, of muon with a precision 140 parts-per-billion. This requires precise measurement both spin precession frequency, ωa, muons stored in field 1.45 T, and that terms shielded proton Larmor ω'p. ω'p total systematic uncertainty 70 parts-per-billion involves combination various nuclear resonance (NMR) probes. There are 378 probes mounted fixed locations constantly monitor drifts. A water-based,...
This paper presents the beam dynamics systematic corrections and their uncertainties for Run-1 data set of Fermilab Muon g-2 Experiment. Two to measured muon precession frequency $\omega_a^m$ are associated with well-known effects owing use electrostatic quadrupole (ESQ) vertical focusing in storage ring. An average vertically oriented motional magnetic field is felt by relativistic muons passing transversely through radial electric components created ESQ system. The correction depends on...
The accurate determination of atomic final states following nuclear $\ensuremath{\beta}$ decay plays an important role in several experiments. In particular, the charge state distributions ions are for determinations $\ensuremath{\beta}\text{\ensuremath{-}}\ensuremath{\nu}$ angular correlation with improved precision. Beyond hydrogenic cases, neutral $^{6}\mathrm{He}$ presents simplest case. Our measurement aims at providing benchmarks to test theoretical calculations. kinematics...
The 6He nucleus is an ideal candidate to study the weak interaction. To this end we have built a high-intensity source of delivering ~10^10 atoms/s experiments. Taking full advantage that available intensity performed high-precision measurement half-life directly probes axial part nuclear Hamiltonian. Currently, are preparing beta-neutrino angular correlation in beta decay will allow search for new physics beyond Standard Model form tensor currents.
A unitary transformation approach is used to study the energy level shift of atom coupled both a vacuum electromagnetic field and driving laser. The Lamb levels shown depend on Rabi frequency detuning laser, which couples another pair levels.
We present details of a high-accuracy absolute scalar magnetometer based on pulsed proton NMR. The $B$-field magnitude is determined from the precession frequency spins in cylindrical sample water after accounting for field perturbations probe materials, shape, and other corrections. Features design, testing procedures, corrections necessary qualification as an are described. device was tested at $B = 1.45$\,T but can be modified range exceeding 1--3\,T. used to calibrate NMR magnetometers...
Correlations between β decay products are sensitive observables to look for exotic contributions the weak interaction excluded by Standard Model of particle physics. To precisely measure – v angular correlation parameter, αβν, in 6He decay, radioactive atoms trapped a magneto-optical trap and momentum particles 6Li recoil ions measured coincidence. The shake-off process, leading higher charge states Li, plays an important role this observation must be studied carefully. Its study provides...