E. J. Stephenson
A5024633000- Nuclear physics research studies
- Nuclear Physics and Applications
- Quantum Chromodynamics and Particle Interactions
- Atomic and Subatomic Physics Research
- Particle physics theoretical and experimental studies
- Particle Accelerators and Free-Electron Lasers
- Advanced NMR Techniques and Applications
- Dark Matter and Cosmic Phenomena
- High-Energy Particle Collisions Research
- Advanced Chemical Physics Studies
- Particle accelerators and beam dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Superconducting Materials and Applications
- Atomic and Molecular Physics
- Quantum, superfluid, helium dynamics
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Surface Roughness and Optical Measurements
- Particle Detector Development and Performance
- Non-Destructive Testing Techniques
- Crystallography and Radiation Phenomena
- Nuclear reactor physics and engineering
- Computational Physics and Python Applications
- Astronomical and nuclear sciences
- Radiation Therapy and Dosimetry
Indiana University Bloomington
2014-2024
Indiana University
1986-2024
Western University
2024
Tulane University
2017-2021
Barts Health NHS Trust
2014-2019
Society of Thoracic Surgeons
2015
London Chest Hospital
2013
University of Ferrara
2012
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati
2012
University of Groningen
2009-2012
A new experiment is described to detect a permanent electric dipole moment of the proton with sensitivity $10^{-29}e\cdot$cm by using polarized "magic" momentum $0.7$~GeV/c protons in an all-electric storage ring. Systematic errors relevant are discussed and techniques address them presented. The measurement sensitive physics beyond Standard Model at scale 3000~TeV.
The proton yields from the interaction of pions on nuclear targets with $12<~A<~181$ were measured in region $\ensuremath{\Delta}(3, 3)$ resonance. shift energies angle is analyzed terms average number nucleons that have participated absorbing pion's momentum and total energy. effective interacting nucleons, for both ${\ensuremath{\pi}}^{+}$ ${\ensuremath{\pi}}^{\ensuremath{-}}$ incident, found to be \ensuremath{\sim} 3 $^{12}\mathrm{C}$ increasing 5.5 $^{181}\mathrm{Ta}$. These numbers are...
The half-life of $^{32}\mathrm{Si}$ has been measured to be ${T}_{\frac{1}{2}}=101\ifmmode\pm\else\textpm\fi{}18$ yr, considerably shorter than the previously accepted value \ensuremath{\approx} 300 yr. new was obtained by measuring specific $\ensuremath{\beta}$ activity with a liquid-scintillation-counter technique and concentration tandem-accelerator mass spectrometry. It is expected that present result will have strong impact on studies cosmogenic $^{32}\mathrm{Si}$.
Based on the notion that local dark-matter field of axions or axionlike particles (ALPs) in our Galaxy induces oscillating couplings to spins nucleons and nuclei (via electric dipole moment latter and/or paramagnetic axion-wind effect), we establish feasibility a new method search for ALPs storage rings. previous work allows us maintain in-plane polarization stored deuteron beam few hundred seconds, perform first proof-of-principle experiment at Cooler Synchrotron (COSY) scan momenta near...
This paper presents the successful application of a phase-lock feedback system to maintain resonance condition radio frequency (rf) spin rotator (specifically, an rf Wien filter) with respect 120 kHz precession in Cooler Synchrotron (COSY) storage ring. Real-time monitoring and filter signal allows relative phase between two be stabilized at arbitrary setpoint. The compensates for deviations by adjusting and/or as needed. With this method, variation demand standard deviation...
Fragmentation and splitting of the Gamow-Teller (GT) strength has been observed in a systematic study ${(}^{3}$He,t) charge-exchange reaction at E${(}^{3}$He)=200 MeV over entire range stable Sn isotopes. Triton energy spectra were with high-resolution magnetic spectrometer angles near \ensuremath{\theta}=0\ifmmode^\circ\else\textdegree\fi{} where \ensuremath{\Delta}L=0 transitions are enhanced. Excitation energies, widths, 0\ifmmode^\circ\else\textdegree\fi{} cross sections, strengths B(GT)...
▪ Abstract Charge symmetry breaking (CSB) in the strong interaction occurs because of difference between masses up and down quarks. The use effective field theories allows us to follow this influence confined quarks hadronic nuclear systems. We review progress observing understanding CSB, with particular attention recent successful observations CSB measurements involving production a single neutral pion, related theoretical progress.
Quarks of charge +1 and other anomalous hydrogen have been sought by using the 88-inch cyclotron at Berkeley as a high-energy mass spectrometer, with natural deuterium sources ions. No quarks were observed, limits placed on their ratio to protons earth that vary from < 2 × 10 –19 for high masses (3 8.2 atomic units) –13 lowest (< 1/3 unit).
The age of a sample carbon dioxide has been determined by accelerating the with cyclotron and detecting carbon-14 ions in beam. Nitrogen-14 was eliminated as background through use range-separation technique. To avoid all possibility experimenter bias, measurement conducted blind fashion.
This Letter reports the successful use of feedback from a spin polarization measurement to revolution frequency $0.97\text{ }\text{ }\mathrm{GeV}/c$ bunched and polarized deuteron beam in Cooler Synchrotron (COSY) storage ring order control both precession rate ($\ensuremath{\approx}121\text{ }\mathrm{kHz}$) phase horizontal component. Real time synchronization with radio (rf) solenoid made possible rotation out plane, yielding demonstration method manipulate polarization. In particular,...
We report the first result for electron-antineutrino angular correlation ($a$ coefficient) in free neutron $\ensuremath{\beta}$ decay from aCORN experiment. uses a novel method which $a$ coefficient is proportional to an asymmetry proton time of flight events where electron and recoil are detected delayed coincidence. Data presented 15 month run at NIST Center Neutron Research. obtained...
The aCORN experiment measures the neutron-decay electron-antineutrino correlation ($a$ coefficient) using a novel method based on an asymmetry in proton time-of-flight for events where beta electron and recoil are detected delayed coincidence. We report data analysis result from second run at NIST Center Neutron Research, high-flux cold neutron beam new NG-C guide end position:...
A concise demonstrative summary of the Symmetric Hybrid ring design for storage proton electric dipole moment experiment is presented. Critical issues such as lattice design, background electrical fields,geometrical phase, general relativity, spin coherence time and polarimeter systematics are Overall, we find that with currently proposed iteration, systematic error sources reduced by orders magnitude alignment requirements within available technology.
We used the $^{16}\mathrm{O}$${(}^{3}$He,n${)}^{18}$Ne, $^{12}\mathrm{C}$${(}^{12}$C${,}^{6}$He${)}^{18}$Ne, and $^{20}\mathrm{Ne}$(p,t${)}^{18}$Ne reactions to study $^{18}\mathrm{Ne}$ states up an excitation energy of 10 MeV, with emphasis on levels corresponding $^{14}\mathrm{O}$(\ensuremath{\alpha},p${)}^{17}$F $^{17}\mathrm{F}$(p,\ensuremath{\gamma}${)}^{18}$Ne resonances that could strongly affect these reaction rates in hot stellar environments. Excitation energies, widths, absolute...
A systematic set of measurements pion and proton yields from reactions on nuclei $4\ensuremath{\le}A\ensuremath{\le}180$ has been performed for incident pions in the $\ensuremath{\Delta}(3,3)$ energy region. Detailed spectra protons at many angles were obtained along with inclusive yields. The implications general features these data absorption scattering processes are discussed.[NUCLEAR REACTIONS $^{4}\mathrm{He}$, $^{6}\mathrm{Li}$, $^{9}\mathrm{Be}$, $^{12}\mathrm{C}$, $^{27}\mathrm{Al}$,...
This paper describes a time-marking system that enables measurement of the in-plane (horizontal) polarization 0.97-GeV/c deuteron beam circulating in Cooler Synchrotron (COSY) at Forschungszentrum J\"ulich. The clock time each polarimeter event is used to unfold 120-kHz spin precession and assign events bins according direction horizontal polarization. After accumulation for one or more seconds, down-up scattering asymmetry can be calculated matched sinusoidal function whose magnitude...
The isoscalar giant dipole resonance (ISGDR) in ${}^{208}\mathrm{Pb}$ has been investigated using inelastic scattering of 200 MeV $\ensuremath{\alpha}$ particles at and near 0\ifmmode^\circ\else\textdegree\fi{} where the angular distribution ISGDR can be clearly differentiated from those other modes. ``difference spectra'' technique was employed to separate high-energy octupole (HEOR). These data provide clearest evidence yet for adjacent HEOR. With these results, all expected...
We report the first observation of charge symmetry breaking $d+d\ensuremath{\rightarrow}^{4}\mathrm{H}\mathrm{e}+{\ensuremath{\pi}}^{0}$ reaction near threshold. Measurements using a magnetic channel (gated by two photons) $^{4}\mathrm{H}\mathrm{e}$ scattering angle and momentum (from time flight) permitted reconstruction ${\ensuremath{\pi}}^{0}$ ``missing mass,'' quantity used to separate $^{4}\mathrm{H}\mathrm{e}+{\ensuremath{\pi}}^{0}$ events from continuum double radiative capture...
Isospin is a good quantum number under the assumption that nuclear interaction charge independent. An analogous structure of excited states expected for nuclei with same mass $A$ but different $z$ components ${T}_{z}$ isospin $T$, where ${T}_{z}=(N\ensuremath{-}Z)/2$. The has been studied isobaric $^{58}\mathrm{Ni}$ and $^{58}\mathrm{Cu}$ by comparing transitions from ground state (initial ${T}_{i}=1$ ${J}^{\ensuremath{\pi}}={0}^{+}$) to $M1$ Gamow-Teller (GT)...
The proposed method exploits charged particles confined as a storage ring beam (proton, deuteron, possibly $^3$He) to search for an intrinsic electric dipole moment (EDM) aligned along the particle spin axis. Statistical sensitivities could approach 10$^{-29}$ e$\cdot$cm. challenge will be reduce systematic errors similar levels. adjusted preserve polarisation, initially parallel velocity, times in excess of 15 minutes. Large radial fields, acting through EDM, rotate polarisation from...
Angular distributions of the three tensor analyzing powers have been measured for ($d, p$) reactions on $^{52}\mathrm{Cr}$, $^{90}\mathrm{Zr}$, and $^{208}\mathrm{Pb}$. Distorted-wave calculations are inconsistent with measurements if deuteron $D$ state is ignored. However, excellent agreement obtained when effects included. We discuss dependence incident energy, $Q$ value, angular momentum transfer.