G. D. Cates
A5064442260- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
- Advanced NMR Techniques and Applications
- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Nuclear Physics and Applications
- Advanced MRI Techniques and Applications
- Nuclear physics research studies
- Dark Matter and Cosmic Phenomena
- High-Energy Particle Collisions Research
- Cold Atom Physics and Bose-Einstein Condensates
- Photocathodes and Microchannel Plates
- Particle Detector Development and Performance
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Atomic and Molecular Physics
- Electron and X-Ray Spectroscopy Techniques
- Radiation Detection and Scintillator Technologies
- NMR spectroscopy and applications
- Neutrino Physics Research
- Advanced Chemical Physics Studies
- Pulsars and Gravitational Waves Research
- Physics of Superconductivity and Magnetism
- Crystallography and Radiation Phenomena
- Methane Hydrates and Related Phenomena
University of Virginia
2015-2025
École Polytechnique
2012
Thomas Jefferson National Accelerator Facility
2010
William & Mary
2009
Williams (United States)
2009
Princeton University
1996-2008
Duke University
1995-2006
United States University
2002
Massachusetts Institute of Technology
2001
Duke University Hospital
1995
We report the first measurement of parity-violating asymmetry APV in elastic scattering polarized electrons from Pb208. is sensitive to radius neutron distribution (Rn). The result APV=0.656±0.060(stat)±0.014(syst) ppm corresponds a difference between radii and proton distributions Rn−Rp=0.33−0.18+0.16 fm provides electroweak observation skin which expected heavy, neutron-rich nucleus.Received 12 January 2012DOI:https://doi.org/10.1103/PhysRevLett.108.112502© 2012 American Physical Society
The spin structure function of the neutron gn1 has been determined over range 0.03<x<0.6 at an average Q2 2 (GeV/c)2 by measuring asymmetry in deep inelastic scattering polarized electrons from a 3He target energies between 19 and 26 GeV. integral is found to be F10gn1(x)dx=-0.022±0.011. Earlier reported proton results together with Bjorken sum rule predict F10gn1(x)dx=-0.059±0.019.Received 1 April 1993DOI:https://doi.org/10.1103/PhysRevLett.71.959©1993 American Physical Society
We report a precision measurement of the parity-violating asymmetry $A_{PV}$ in elastic scattering longitudinally polarized electrons from $^{208}$Pb. measure $A_{PV}=550\pm 16 {\rm (stat)}\pm 8\ (syst)}$ parts per billion, leading to an extraction neutral weak form factor $F_W(Q^2 = 0.00616\ GeV}^2) 0.368 \pm 0.013$. Combined with our previous measurement, extracted neutron skin thickness is $R_n-R_p=0.283 0.071$~fm. The result also yields first significant direct interior density...
We report a precise measurement of the parity-violating (PV) asymmetry A_{PV} in elastic scattering longitudinally polarized electrons from ^{48}Ca. measure A_{PV}=2668±106(stat)±40(syst) parts per billion, leading to an extraction neutral weak form factor F_{W}(q=0.8733 fm^{-1})=0.1304±0.0052(stat)±0.0020(syst) and charge minus F_{ch}-F_{W}=0.0277±0.0055. The resulting neutron skin thickness R_{n}-R_{p}=0.121±0.026(exp)±0.024(model) fm is relatively thin yet consistent with many model...
Abstract Magnetic resonance images of the lungs a guinea pig have been produced using hyperpolarized helium as source MR signal. The resulting are not yet sufficiently optimized to reveal fine structural detail within lung, but spectacular signal from this normally signal‐deficient organ system offers great promise for eventual in vivo imaging experiments. Fast 2D and 3D GRASS sequences with very small flip angles were employed conserve nonrenewable longitudinal magnetization. We discuss...
A method is described for producing several liters of nuclear spin polarized 129Xe gas via exchange with an optically pumped Rb vapor. We use a 140 W AlGaAs laser diode array whose broad spectral output efficiently absorbed by employing ∼10 atm 4He to pressure broaden the D1 absorption profile. in continuous flow and then cryogenically accumulated stored. Extensions this technique should enable production tens polarization order 50%. Production laser-polarized liter quantities important...
Using a new method of xenon laser-polarization that permits the generation liter quantities hyperpolarized 129Xe gas, first imaging results from human chest and spectroscopy head have been obtained. With polarization levels approximately 2%, cross-sectional images lung gas-spaces with voxel volume 0.9 cm3 (signal-to-noise ratio (SNR), 28) were acquired three dissolved-phase resonances in spectra detected. In head, one prominent resonance, presumably brain parenchyma, was anticipated...
Two healthy volunteers who had inhaled approximately 0.75 L of laser-polarized helium-3 gas underwent magnetic resonance imaging at 1.5 T with fast gradient-echo pulse sequences and small flip angles ( < 10 degrees). Thick-section (20 mm) coronal images, time-course data (30 images collected every 1.8 seconds), thin-section (6 were acquired. Subjects able to breathe the (12% polarization) without difficulty. good quality a signal-to-noise ratio (S/N) 32:1 near surface coil 16:1 farther away....
The neutron longitudinal and transverse asymmetries A1n A2n have been extracted from deep inelastic scattering of polarized electrons by a He3 target at incident energies 19.42, 22.66, 25.51 GeV. measurement allows for the determination spin structure functions g1n(x, Q2) g2n(x, over range 0.03<x<0.6 an average Q2 2 (GeV/c)2. data are used evaluation Ellis-Jaffe Bjorken sum rules. function is small negative within our measurement, yielding integral ∫0.030.6g1n(x)dx=−0.028±0.006 (stat)±0.006...
We have developed a theory for the effect of magnetic-field inhomogeneities on spin relaxation gases in cells with negligible at walls. There is characteristic pressure ${p}^{\mathrm{*}}$ which time ${\ensuremath{\tau}}_{d}$ required an atom to diffuse across cell equal ${\ensuremath{\tau}}_{l}$ precess by one radian mean magnetic field. For ``high pressures,'' p\ensuremath{\gg}${p}^{\mathrm{*}}$, longitudinal spin-relaxation ${T}_{1}$ inversely proportional pressure. This classic dependence...
We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Møller) scattering: A(PV) = [-131 +/- 14(stat) 10(syst)] x 10(-9), leading to determination weak mixing angle sin2(thetaW(eff) 0.2397 0.0010(stat) 0.0008(syst), evaluated at Q2 0.026 GeV2. Combining this result with measurements Z0 pole, running is observed over 6sigma significance. The sets constraints new physics effects TeV scale.
Thirty-two magnetic resonance imaging examinations of the lungs were performed in 16 subjects after inhalation 1–2 L helium 3 gas that was laser polarized to 10%–25%. The distribution generally uniform, with visualization fissures most cases. Ventilation defects demonstrated smokers and a subject allergies. technique has potential for evaluating small airways disease.
We report the first measurement of target single spin asymmetries in semi-inclusive $^3{He}(e,e'\pi^\pm)X$ reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using 5.9 GeV electron beam, covers range 0.14 $< x <$ 0.34 with 1.3 $<Q^2<$ 2.7 GeV$^2$. Collins and Sivers moments were extracted from azimuthal angular dependence measured asymmetries. $\pi^\pm$ for $^3$He are consistent zero, except $\pi^+$ moment $x=0.34$, which deviates zero by 2.3$\sigma$....
We report new measurements of the parity-violating asymmetry ${A}_{\mathrm{PV}}$ in elastic scattering 3 GeV electrons off hydrogen and $^{4}\mathrm{He}$ targets with $⟨{\ensuremath{\theta}}_{\mathrm{lab}}⟩\ensuremath{\approx}6.0\ifmmode^\circ\else\textdegree\fi{}$. The result is ${A}_{\mathrm{PV}}=\mathbf{(}+6.40\ifmmode\pm\else\textpm\fi{}0.23(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.12(\mathrm{syst})\mathbf{)}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$....
We studied the line shape of Rb ${D}_{1}$ and ${D}_{2}$ resonance lines in presence 1--10 amg several gases: ${}^{3}$He, ${}^{4}$He, N${}_{2}$, Xe. found that cores are well described by asymmetric expected for a van der Waals interatomic potential. The width shift is proportional to density foreign gas with high degree accuracy, while asymmetry independent density. constants proportionality pressure broadening were measured much higher accuracy than previous experiments. also dependence...
We have measured the parity-violating electroweak asymmetry in elastic scattering of polarized electrons from protons. Significant contributions to this could arise strange form factors nucleon. The is $A=\ensuremath{-}15.05\ifmmode\pm\else\textpm\fi{}0.98(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.56(\mathrm{syst})\phantom{\rule{0.3em}{0ex}}\mathrm{ppm}$ at kinematic point $⟨{\ensuremath{\theta}}_{\mathrm{lab}}⟩=12.3\ifmmode^\circ\else\textdegree\fi{}$ and...
We report on measurements of the neutron spin asymmetries An1,2 and polarized structure functions gn1,2 at three kinematics in deep inelastic region, with x=0.33, 0.47, 0.60 Q2=2.7, 3.5, 4.8(GeV∕c)2, respectively. These were performed using a 5.7GeV longitudinally electron beam 3He target. The results for An1 gn1 x=0.33 are consistent previous world data and, two higher-x points, have improved precision by about an order magnitude. new show zero crossing around x=0.47 value x=0.60 is...
Dark sectors, consisting of new, light, weakly-coupled particles that do not interact with the known strong, weak, or electromagnetic forces, are a particularly compelling possibility for new physics. Nature may contain numerous dark each their own beautiful structure, distinct particles, and forces. This review summarizes physics motivation sectors exciting opportunities experimental exploration. It is summary Intensity Frontier subgroup "New, Light, Weakly-coupled Particles" Community...
The Q(weak) experiment has measured the parity-violating asymmetry in ep elastic scattering at Q(2)=0.025(GeV/c)(2), employing 145 μA of 89% longitudinally polarized electrons on a 34.4 cm long liquid hydrogen target Jefferson Lab. results experiment's commissioning run, constituting approximately 4% data collected experiment, are reported here. From these initial results, is A(ep)=-279±35 (stat) ± 31 (syst) ppb, which smallest and most precise ever scattering. small Q(2) this made possible...
The u- and d-quark contributions to the elastic nucleon electromagnetic form factors have been determined by using experimental data on G(E)(n), G(M)(n), G(E)(p), G(M)(p). Such a flavor separation of became possible up negative four-momentum transfer squared Q(2) = 3.4 GeV(2) with recent G(E)(n) from Hall A at Jefferson Lab. For above 1 GeV(2), for both u d quark, ratio Pauli Dirac factors, F(2)/F(1), was found be almost constant in sharp contrast behavior F(2)/F(1) proton as whole. Also,...