A. Schmidt
A5042390691- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Atomic and Molecular Physics
- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Particle Accelerators and Free-Electron Lasers
- Cosmology and Gravitation Theories
- Neutrino Physics Research
- Sociology and Education Studies
- Superconducting Materials and Applications
- Advanced Chemical Physics Studies
- Astronomical and nuclear sciences
- Particle accelerators and beam dynamics
- Public Administration and Political Analysis
- Advanced NMR Techniques and Applications
- Muon and positron interactions and applications
- Radiation Detection and Scintillator Technologies
- Linguistic research and analysis
- Corporate Governance and Management
- Computational Physics and Python Applications
- Medical and Health Sciences Research
George Washington University
2020-2025
Massachusetts Institute of Technology
2014-2024
Thomas Jefferson National Accelerator Facility
2023-2024
National Nuclear Energy Agency of Indonesia
2024
National Research and Innovation Agency
2024
Institute of High Energy Physics
2024
University of Antwerp
2024
A. Alikhanyan National Laboratory
2024
Campbell Collaboration
2023
James Madison University
2023
We measured the triple coincidence A(e,e'np) and A(e,e'pp) reactions on carbon, aluminum, iron, lead targets at Q2 > 1.5 (GeV/c)2, xB 1.1 missing momentum 400 MeV/c. This was first direct measurement of both proton-proton (pp) neutron-proton (np) short-range correlated (SRC) pair knockout from heavy asymmetric nuclei. For all nuclei, average to reduced cross-section ratio is about 6%, in agreement with previous indirect measurements. Correcting for Single-Charge Exchange effects decreased...
The OLYMPUS Collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, R_{2γ}, direct measure contribution hard two-photon exchange section. In measurement, 2.01 GeV electron and positron beams were directed through hydrogen gas target internal DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers time-of-flight scintillators detected elastically scattered leptons in coincidence recoiling...
Exclusive measurements of the quasifree $pn\ensuremath{\rightarrow}pp{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}$ reaction have been performed by means $pd$ collisions at ${T}_{p}$ $=$ 1.2 GeV using wide angle shower apparatus (WASA) detector setup cooler synchrotron COSY (Institut f\"ur Kernphysik, J\"ulich). Total and differential cross sections obtained covering energy region $\sqrt{s}$ (2.35--2.46) GeV, which includes ABC effect its associated resonance structure. No...
High-energy electron scattering is a clean and precise probe for measurements of hadronic nuclear structure, with key role in understanding the high-momentum nucleons (and quarks) nuclei. Jefferson Lab has dramatically expanded our generated by short-range correlations, providing sufficient insight to model much their impact on structure neutron stars, low- medium-energy observables including neutrino oscillation measurements. These correlations also appear be related modification quark...
An exclusive measurement of the excitation function for dd->3Heppi- reaction was performed at Cooler Synchrotron COSY-Juelich with WASA-at-COSY detection system. The data were taken during a slow acceleration beam from 2.185 GeV/c to 2.400 crossing kinematic threshold eta meson production in dd->4He-eta 2.336 GeV/c. corresponding excess energy respect 4He-eta system varied -51.4MeV 22MeV. integrated luminosity experiment determined using dd->3Hen reaction. shape examined. No signal bound...
Short-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all nucleons with momentum greater than Fermi (${k}_{F}$). A fundamental characteristic SRC is having large relative momenta as compared to ${k}_{F}$, and smaller center mass (c.m.) which indicates small separation distance between in pair. Determining c.m. distribution essential understanding their formation process. We report here on extraction motion proton-proton ($pp$) carbon and, first...
High-momentum configurations of nucleon pairs at short-distance are probed using measurements the $^{12}$C$(e,e'p)$ and $^{12}$C$(e,e'pN)$ reactions (where $N$ is either $n$ or $p$), high-$Q^2$ $x_B>1.1$. The data span a missing-momentum range 300--1000 MeV/c predominantly sensitive to transition region strong nuclear interaction from Tensor Scalar interaction. well reproduced by theoretical calculations Generalized Contact Formalism with both chiral phenomenological nucleon-nucleon...
Short-range correlations (SRCs) are a universal feature of nuclear structure. A wide range measurements, primarily using electron scattering, have revealed SRC properties, such as their abundance in different nuclei, well the strong preference for proton-neutron pairing over proton-proton or neutron-neutron pairing. Despite inherent complexity many-body systems, number salient features scattering measurements described by simple, factorized theory called Generalized Contact Formalism. key...
Photoluminescence studies on InGaAs/GaAs quantum dots with diameters down to 20 nm have been performed in magnetic fields up $B\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}12$ T and compared detailed calculations. The eigenstates of these cylindrical are characterized by a radial number an azimuthal corresponding the orbital angular momentum. From distinctly different field dependences several transitions we identify electron-hole recombinations involving states 0,...
Mechanisms of spin-flavor SU(6) symmetry breaking in quantum chromodynamics (QCD) are studied via an extraction the free neutron structure function from a global analysis deep inelastic scattering (DIS) data on proton and nuclei A=2 (deuterium) to 208 (lead). Modification nucleons bound atomic (known as EMC effect) consistently accounted for within framework universal modification short-range correlated (SRC) pairs. Our extracted neutron-to-proton ratio F_{2}^{n}/F_{2}^{p} becomes constant...
Measurements of short-range correlations in exclusive $^4$He$(e,e'pN)$ reactions are analyzed using the Generalized Contact Formalism (GCF). We consider both instant-form and light-cone formulations with AV18 local N2LO(1.0) nucleon-nucleon ($NN$) potentials. find that kinematic distributions, such as reconstructed pair opening angle, recoil neutron momentum distribution, center mass motion, well measured missing energy, all reproduced by GCF calculations. The dependence / $^4$He$(e,e'p)$...
Pair densities and associated correlation functions provide a critical tool for introducing many-body correlations into wide-range of effective theories. Ab initio calculations show that two-nucleon pair-densities exhibit strong spin isospin dependence. However, such are not available all nuclei current interest. We therefore simple model, which involves combining the short long separation distance behavior using single blending function, to accurately describe inherent in existing ab...
The extraction of the relative abundances short-range correlated (SRC) nucleon pairs from inclusive electron scattering is studied using generalized contact formalism (GCF) with several nuclear interaction models. GCF calculations can reproduce observed scaling cross-section ratios for nuclei to deuterium at high-$x_B$ and large-$Q^2$, $a_2=(\sigma_A/A)/(\sigma_d/2)$. In non-relativistic instant-form formulation, calculation very sensitive model parameters only reproduces data that are...
We report on the results of first search for production axion-like particles (ALPs) via Primakoff nuclear targets, γA→aA, in "SRC-CT" experiment using GlueX detector at Jefferson Lab. This uses an integrated luminosity 100 pb⋅−1nucleon a 12C target with real photon beam energies 6<Eγ<10.8 GeV, and explores mass region 200<ma<450 MeV decay a→γγ. range is between π0 η meson masses, which enables use measured rate to obtain absolute bounds ALP reduced sensitivity experimental detection...