D. M. Keller
A5033920290- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Computational Physics and Python Applications
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Superconducting Materials and Applications
- Advanced NMR Techniques and Applications
- Dark Matter and Cosmic Phenomena
- Particle Accelerators and Free-Electron Lasers
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Nuclear Physics and Applications
- Quantum, superfluid, helium dynamics
- Black Holes and Theoretical Physics
- Nuclear physics research studies
- Stochastic processes and statistical mechanics
- Astro and Planetary Science
- Molecular Spectroscopy and Structure
- Combustion and Detonation Processes
- High-pressure geophysics and materials
- Fault Detection and Control Systems
- Cold Atom Physics and Bose-Einstein Condensates
- Astronomy and Astrophysical Research
Syracuse University
2022-2024
University of Virginia
2014-2024
McCormick (United States)
2014-2024
University of Zagreb
2024
University of Saskatchewan
2024
Monash University
2023
New York University
2022
University of York
2021
KU Leuven
2016-2019
Institute of Astronomy
2018-2019
High-statistics measurements of differential cross sections and recoil polarizations for the reaction $\gamma p \rightarrow K^+ \Sigma^0$ have been obtained using CLAS detector at Jefferson Lab. We cover center-of-mass energies ($\sqrt{s}$) from 1.69 to 2.84 GeV, with an extensive coverage in $K^+$ production angle. Independent were made $K^{+}p\pi^{-}$($\gamma$) $K^{+}p$($\pi^-, \gamma$) final-state topologies, found exhibit good agreement. Our show agreement earlier CLAS, SAPHIR LEPS...
The physics case and an experimental overview of the MOLLER (Measurement Of a Lepton Electroweak Reaction) experiment at 12 GeV upgraded Jefferson Lab are presented. A highlight Fundamental Symmetries subfield 2007 NSAC Long Range Plan was SLAC E158 measurement parity-violating asymmetry $A_{PV}$ in polarized electron-electron (M{\o}ller) scattering. proposed will improve on this result by factor five, yielding most precise weak mixing angle low or high energy anticipated over next decade....
We provide the general expression of cross section for exclusive deeply virtual photon electroproduction from a spin 1/2 target using current parameterizations off-forward correlation function in nucleon different beam and polarization configurations up to twist three accuracy. All contributions including Compton scattering, Bethe-Heitler process, their interference, are described within helicity amplitude based framework which is also relativistically covariant readily applicable both...
The Σ(1385) resonance, or Σ*, is well known as part of the standard baryon decuplet with spin J=32. Measurements reaction γp→K+Σ*0 are difficult to extract due overlap nearby Λ(1405) resonance. However, γn→K+Σ*− has no its charge. Here we report first measurement cross sections and beam asymmetries for photoproduction Σ*− from a deuteron target. at forward angles range 0.4 1.2 μb, broad maximum near Eγ≃1.8 GeV. negative, in contrast positive values γn→K+Σ− reaction.Received 19 September...
Red supergiant stars are surrounded by a gaseous and dusty circumstellar environment created their mass loss, which spreads heavy elements into the interstellar medium. The structure dynamics of this envelope crucial to understand processes driving red loss shaping pre-supernova ejecta. We have observed emission from CO J = 2 − 1 line star |$\mu$| Cep with NOEMA interferometer. In synthesized beam was 0.92 × 0.72 arcsec (590 462 au at 641 pc). continuum map shows only unresolved contribution...
(abridged) In the inner regions of AGB outflows, several molecules have been detected with abundances much higher than those predicted from thermodynamic equilibrium (TE) chemical models. The presence majority these species can be explained by shock-induced non-TE models, where shocks caused pulsating star take chemistry out TE in region. Moreover, a non-uniform density structure has outflows. A detailed parameter study on quantitative effects non-homogeneous outflow so far not performed. We...
LHCSpin aims at installing a polarized gas target in front of the LHCb spectrometer, bringing, for first time, physics to LHC. The project will benefit from experience achieved with installation an unpolarized during LHC Long Shutdown 2. then become experiment simultaneously running collider and fixed-target mode targets, opening whole new range explorations its exceptional spectrometer. offer unique opportunity probe quark gluon parton distributions nucleons nuclei, especially high $x$...
We present new Effelsberg-100 m, ATCA, and VLA observations of rotational SiS transitions in the circumstellar envelope (CSE) IRC +10216. Thanks to high angular resolution achieved by ATCA observations, we unambiguously confirm that molecule's J=1-0 transition exhibits maser action this CSE, as first suggested more than thirty years ago. The emission's radial velocity peaking at a local standard rest -39.862$\pm$0.065 km/s indicates it arises from an almost fully accelerated shell....
The study of hyperon resonances has entered a new era precision with advent high-statistics photoproduction data from the CLAS detector at Jefferson Lab. These have multi-particle final states, allowing clean identification exclusive reactions associated strange mesons and baryons. Examples physics results are: evidence for isospin interference in decay $\Lambda(1405)$ resonance; strong suggestion meson cloud effects structure $\Sigma(1385)$ $K^*$ that will test existence purported...
The interpretation of the signals detected by high precision experiments aimed at measuring neutrino oscillations requires an accurate description neutrino-nucleus cross sections. One key element analysis is treatment nuclear effects, which one main sources systematics for accelerator based such as Long Baseline Neutrino Experiment (LBNE). A considerable effort currently being made to develop theoretical models capable providing a fully quantitative sections in kinematical regime relevant...
We report measurements of π+ and π0 meson photoproduction from longitudinally spin-polarised protons by an energy tagged (0.73-2.3 GeV) linearly polarised photon beam. A close to complete solid angle coverage for the reaction products was provided CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The double-polarisation observable G is extracted Maximum Likelihood fits data, enabling first accurate determination γ→p→→π+n, while also significantly extending kinematic γ→p→→π0p. This...
This workshop aimed at producing an optimized photon source concept with potential increase of scientific output Jefferson Lab, and refining the science for hadron physics experiments benefitting from such a high-intensity source. The brought together communities directly using sources photo-production experiments, or conversion into $K_L$ beams. combination high precision calorimetry intensity greatly enhances benefit to (deep) exclusive processes like wide-angle time-like Compton...
Although the proton was discovered about 100 years ago, its spin structure still remains a mystery. Recent studies suggest that orbital angular momentum of sea quarks could significantly contribute to proton's spin. The SeaQuest experiment, which recently completed data collection, probed unpolarized light quark distributions using Drell-Yan process. Its successor, SpinQuest (E1039), will access $\bar{u}$ and $\bar{d}$ Sivers functions polarized NH$_3$ ND$_3$ targets. A non-zero asymmetry,...
One in 5 planetary nebulae are ejected from common envelope binary interactions but Kepler Space Telescope results already showing this proportion to be larger. Their properties, such as abundances can starkly different those of the general population, so they should considered separately when using PN chemical or population probes. Unfortunately post-common cannot discerned only their morphologies, will change once we couple our new simulations with formation models.
This document describes the technical design concept of a compact high intensity, multi-GeV photon source. Capable producing 10^12 equivalent photons per second this novel device will provide unprecedented access to physics processes with very small scattering probabilities such as hard exclusive reactions on nucleon. When combined dynamic nuclear polarized targets, its deployment result in large gain experiment figure-of-merit compared all previous measurements. Compared traditional...
Context. HCN is a major constituent of the circumstellar envelopes carbon-rich evolved stars, and rotational lines from within its vibrationally excited states probe parts these regions closest to stellar surface. A number such are known show maser action. Historically, in one them, 177 GHz $J=2\rightarrow1$ line $l$-doubled bending mode has been found relatively strong action, with results only published for single object, archetypical high-mass loss asymptotic giant branch (AGB) star...