E.V. Hungerford
A5086602208- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Nuclear physics research studies
- Particle Detector Development and Performance
- Nuclear Physics and Applications
- Dark Matter and Cosmic Phenomena
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Atomic and Subatomic Physics Research
- Atomic and Molecular Physics
- Superconducting Materials and Applications
- Quantum, superfluid, helium dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced NMR Techniques and Applications
- CCD and CMOS Imaging Sensors
- Muon and positron interactions and applications
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Computational Physics and Python Applications
- Magnetic confinement fusion research
- Astrophysics and Cosmic Phenomena
- Medical Imaging Techniques and Applications
- Advanced Chemical Physics Studies
- Radioactive Decay and Measurement Techniques
University of Houston
2011-2024
Auburn University
2024
Forschungszentrum Jülich
2020
RWTH Aachen University
2020
Tohoku University
2013
Hampton University
2012
Brookhaven National Laboratory
1982
Rice University
1970-1981
Oak Ridge National Laboratory
1968-1980
Oak Ridge Associated Universities
1979
An experiment has been performed to search for the muon- and electron-number nonconserving decay μ+→e+γ. The upper limit branching ratio is found be Γ(μ+→e+γ)/ Γ(μ+→e+ν¯ν)<1.2×10−11 with 90% confidence.Received 10 May 1999DOI:https://doi.org/10.1103/PhysRevLett.83.1521©1999 American Physical Society
We present the results of a search for dark matter WIMPs in mass range below 20 GeV/c^2 using target low-radioactivity argon. The data were obtained DarkSide-50 apparatus at Laboratori Nazionali del Gran Sasso (LNGS). analysis is based on ionization signal, which time projection chamber fully efficient 0.1 keVee. observed rate detector 0.5 keVee about 1.5 events/keVee/kg/day and almost entirely accounted by known background sources. obtain 90% C.L. exclusion limit above 1.8 spin-independent...
Liquid argon is a bright scintillator with potent particle identification properties, making it an attractive target for direct-detection dark matter searches. The DarkSide-50 search here reports the first WIMP results obtained using of low-radioactivity argon. detector, two-phase liquid time projection chamber, located at Laboratori Nazionali del Gran Sasso. underground shown to contain Ar-39 level reduced by factor (1.4 +- 0.2) x 10^3 relative atmospheric We report background-free null...
Hypernuclear lifetime and partial decay-rate measurements made at the Brookhaven National Laboratory Alternating Gradient Synchrotron are reported for $_{\mathrm{\ensuremath{\Lambda}}}^{5}\mathrm{He}$ $_{\mathrm{\ensuremath{\Lambda}}}^{12}\mathrm{C}$. The mesonic nonmesonic decays compared to existing weak-interaction calculations. In particular, reaction \ensuremath{\Lambda}N\ensuremath{\rightarrow}NN is discussed as an example of a nonleptonic weak process which calculations have been...
The spectra of levels in the hypernuclei $_{\ensuremath{\Lambda}}^{13}\mathrm{C}$, $_{\ensuremath{\Lambda}}^{14}\mathrm{N}$, and $_{\ensuremath{\Lambda}}^{18}\mathrm{O}$, excited by 800-MeV/c kaons (${K}^{\ensuremath{-}}$,${\ensuremath{\pi}}^{\ensuremath{-}}$) reaction, have been observed at Brookhaven alternating-gradient synchrotron. Data were recorded for scattering angles from 0\ifmmode^\circ\else\textdegree\fi{} to 25\ifmmode^\circ\else\textdegree\fi{}, corresponding momentum transfers...
$\ensuremath{\gamma}$-ray transitions of energy 2.034 \ifmmode\pm\else\textpm\fi{} 0.023 MeV in the hypernucleus $_{\ensuremath{\Lambda}}^{7}\mathrm{Li}$ and 3.079 0.040 $_{\ensuremath{\Lambda}}^{9}\mathrm{Be}$ are observed. In both cases, $\ensuremath{\gamma}$ ray $_{\ensuremath{\Lambda}}^{A}Z$ is very close to first excited state nuclear core. The rays interpreted as arising from core presence $\ensuremath{\Lambda}$ particle. size shift places limits on strength $\ensuremath{\Lambda}N$...
An experiment with a newly developed high-resolution kaon spectrometer (HKS) and scattered electron novel configuration was performed in Hall C at Jefferson Lab (JLab). The ground state of neutron-rich hypernucleus, He 7 Lambda, observed for the first time (e,e'K+) reaction an energy resolution ~0.6 MeV. This is best reported to date hypernuclear spectroscopy. he Lambda binding supplies last missing information A=7, T=1 iso-triplet, providing new input charge symmetry breaking (CSB) effect...
Spectroscopy of a $^{10}_{\Lambda}$Be hypernucleus was carried out at JLab Hall C using the $(e,e^{\prime}K^{+})$ reaction. A new magnetic spectrometer system (SPL+HES+HKS), specifically designed for high resolution hypernuclear spectroscopy, used to obtain an energy spectrum with 0.78 MeV (FWHM). The well-calibrated present experiment $p(e,e^{\prime}K^{+})\Lambda,\Sigma^{0}$ reactions allowed us determine levels, and binding ground state peak (mixture 1$^{-}$ 2$^{-}$ states) obtained be...
We have observed a clear peak below the ${\ensuremath{\Sigma}}^{+}$-production threshold in ${}^{4}\mathrm{He}({K}^{\ensuremath{-}},{\ensuremath{\pi}}^{\ensuremath{-}})$ reaction at $600\mathrm{MeV}/c$ and ${\ensuremath{\theta}}_{K\ensuremath{\pi}}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}4}^{\ensuremath{\circ}}$. This is confirmation of existence bound state ${}_{\ensuremath{\Sigma}}^{4}\mathrm{He}$, which was reported...
A measurement is reported of the mean lifetime, $\ensuremath{\tau}$, for weak decay $_{\ensuremath{\Lambda}}^{12}\mathrm{C}$ and $_{\ensuremath{\Lambda}}^{11}\mathrm{B}$ hypernuclei. The experiment detected energetic protons from hypernuclear nonmesonic $\ensuremath{\Lambda}+p\ensuremath{\rightarrow}n+p$, in coincidence with production by strangeness-changing reactions $^{12}\mathrm{C}({K}^{\ensuremath{-}}, {\ensuremath{\pi}}^{\ensuremath{-}})_{\ensuremath{\Lambda}}^{12}\mathrm{C}$...
The MEGA experiment, which searched for the muon- and electron-number violating decay μ+→e+γ, is described. spectrometer system, calibrations, data taking procedures, analysis, sensitivity of experiment are discussed. most stringent upper limit on branching ratio, B(μ+→e+γ)<1.2×10−11 with 90% confidence, derived from a likelihood analysis.Received 6 November 2001DOI:https://doi.org/10.1103/PhysRevD.65.112002©2002 American Physical Society
Since the pioneering experiment, E89-009 studying hypernuclear spectroscopy using $(e,e^{\prime}K^+)$ reaction was completed, two additional experiments, E01-011 and E05-115, were performed at Jefferson Lab. These later experiments used a modified experimental design, "tilt method", to dramatically suppress large electromagnetic background, allowed for substantial increase in luminosity. Additionally, new kaon spectrometer, HKS (E01-011), electron HES, splitting magnet added produce...
The energy spectra of tritons, $\ensuremath{\alpha}$ particles, and deuterons from the reactions $^{3}\mathrm{He}(d,t)2p$, $d(^{3}\mathrm{He},t)2p$, $^{3}\mathrm{He}(^{3}\mathrm{He},^{4}\mathrm{He})2p$, $p(^{3}\mathrm{He},d)2p$ were measured at forward angles 0\ifmmode^\circ\else\textdegree\fi{} to 5\ifmmode^\circ\else\textdegree\fi{}, using 36-MeV 53-MeV $^{3}\mathrm{He}$ Oak Ridge isochronous cyclotron. reaction $d(^{3}\mathrm{He},t)2p$ was also studied 74 MeV. All had peaks in high-energy...
We present an experimental method for measuring the process of coherent elastic neutrino-nucleus scattering (CENNS). This uses a detector situated transverse to high-energy neutrino beam production target. would be sensitive low-energy neutrinos arising from decay-at-rest pions in discuss physics motivation making this measurement and outline predicted backgrounds sensitivities using approach. report neutron as found off-axis surface location Fermilab Booster Neutrino Beam (BNB) The results...
High-energy, cw electron beams at new accelerator facilities allow electromagnetic production and precision study of hypernuclear structure, we report here on the first experiment demonstrating potential $(e,{e}^{\ensuremath{'}}{K}^{+})$ reaction for spectroscopy. This is also to take advantage enhanced virtual photon flux available when electrons are scattered approximately zero degrees. The observed energy resolution was found be $\ensuremath{\approx}900\text{ }\text{...
Cross sections for semi-inclusive electroproduction of charged pions (π±) from both proton and deuteron targets were measured 0.2<x<0.5, 2<Q2<4 GeV2, 0.3<z<1, Pt2<0.2 GeV2. For Pt<0.1 GeV, we find the azimuthal dependence to be small, as expected theoretically. π+ π−, Pt is found slightly weaker than proton. In context a simple model, this implies that initial transverse momenta width d quarks larger u and, contrary expectations, momentum favored fragmentation function unfavored one.
The differential cross section for the process $p(e,{e}^{'}p)\ensuremath{\eta}$ has been measured at ${Q}^{2}~5.7$ and $7.0(\mathrm{GeV}/c){}^{2}$ center-of-mass energies from threshold to 1.8 GeV, encompassing ${S}_{11}(1535)$ resonance, which dominates channel. This is highest momentum-transfer measurement of this exclusive date. helicity-conserving transition amplitude ${A}_{1/2}$, production extracted data. Within limited ${Q}^{2}$ now measured, quantity appears begin scaling as...
Received 30 April 2012DOI:https://doi.org/10.1103/PhysRevLett.108.199902© 2012 American Physical Society
A pioneering experiment in \ensuremath{\Lambda} hypernuclear spectroscopy, undertaken at the Thomas Jefferson National Accelerator Facility (JLab), was recently reported. The used high precision, continuous electron beam JLab, and a special arrangement of spectrometer magnets to measure spectrum from C $^{7}\mathrm{Li}$ targets using $(e,e'{K}^{+})$ reaction. ${}_{\ensuremath{\Lambda}}^{12}$B found this investigation previously published, but is reported here more detail, with improved...
A search for radiative transitions between 0.100 and 0.9 MeV from the p-shell hypernucleus $_{\mathrm{\ensuremath{\Lambda}}}^{10}\mathrm{B}$ was undertaken. Of special interest are M1 spin-flip members of doublet formed by coupling an s-shell \ensuremath{\Lambda} hyperon to nuclear core. No such were observed in this energy range attributable $_{\mathrm{\ensuremath{\Lambda}}}^{10}\mathrm{B}$. This negative result provides additional constraints on parameters \ensuremath{\Lambda}-nucleon...
Kinematically complete data for the reaction $\mathrm{pp}\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{+}n$ at 800 MeV have been accumulated four proton lab angles (15\ifmmode^\circ\else\textdegree\fi{}, 20\ifmmode^\circ\else\textdegree\fi{}, 25\ifmmode^\circ\else\textdegree\fi{}, and 30\ifmmode^\circ\else\textdegree\fi{}) where cross section $\frac{{d}^{5}\ensuremath{\sigma}}{d{p}_{1}d{\ensuremath{\Omega}}_{1}d{\ensuremath{\Omega}}_{2}}$ is dominated by ${\ensuremath{\Delta}}^{++}$...
A large set of cross sections for semi-inclusive electroproduction charged pions ($\pi^\pm$) from both proton and deuteron targets was measured. The data are in the deep-inelastic scattering region with invariant mass squared $W^2$ > 4 GeV$^2$ range four-momentum transfer $2 < Q^2 4$ (GeV/c)$^2$, cover a Bjorken scaling variable 0.2 x 0.6. fractional energy spans 0.3 z 1, small transverse momenta respect to virtual-photon direction, $P_t^2 0.2$ (GeV/c)$^2$. that goes undetected, $M_x$ or W',...