R. Pedroni
A5090612078- Nuclear physics research studies
- Nuclear Physics and Applications
- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Nuclear reactor physics and engineering
- High-Energy Particle Collisions Research
- Atomic and Molecular Physics
- Medical Imaging Techniques and Applications
- Nuclear Materials and Properties
- Atomic and Subatomic Physics Research
- High-pressure geophysics and materials
- Radiation Detection and Scintillator Technologies
- Astronomical and nuclear sciences
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Particle Accelerators and Free-Electron Lasers
- Radioactive element chemistry and processing
- Superconducting Materials and Applications
- Space Satellite Systems and Control
- Magnetic confinement fusion research
- Rare-earth and actinide compounds
- Astronomical Observations and Instrumentation
- Advanced X-ray and CT Imaging
North Carolina Agricultural and Technical State University
2011-2023
George Washington University
2020
Triangle Universities Nuclear Laboratory
1982-2012
Duke University
1982-2010
Thomas Jefferson National Accelerator Facility
2009
Lawrence Livermore National Laboratory
2008
United States Department of Energy
1985
We report on the measurement of γp→J/ψp cross section from E_{γ}=11.8 GeV down to threshold at 8.2 using a tagged photon beam with GlueX experiment. find that total falls toward less steeply than expected two-gluon exchange models. The differential dσ/dt has an exponential slope 1.67±0.39 GeV^{-2} 10.7 average energy. LHCb pentaquark candidates P_{c}^{+} can be produced in s channel this reaction. see no evidence for them and set model-dependent upper limits their branching fractions...
High precision measurements of the differential cross sections for π0 photoproduction at forward angles two nuclei, 12C and 208Pb, have been performed incident photon energies 4.9-5.5 GeV to extract π0→γγ decay width. The experiment was done Jefferson Lab using Hall B tagger a high-resolution multichannel calorimeter. width extracted by fitting measured recently updated theoretical models process. resulting value is Γ(π0→γγ)=7.82±0.14(stat)±0.17(syst) eV. With 2.8% total uncertainty, this...
Neutron elastic-scattering angular distributions were measured at beam energies of 11.9 and 16.9 MeV on $^{40,48}\mathrm{Ca}$ targets. These data plus other measurements, total reaction cross-sections $(e,{e}^{\ensuremath{'}}p)$ data, single-particle for magic doubly nuclei have been analyzed in the dispersive optical-model (DOM), generating nucleon self-energies (optical-model potentials) that can be related, via many-body Dyson equation, to spectroscopic factors occupation probabilities....
We report measurements of the photon beam asymmetry $\Sigma$ for reactions $\vec{\gamma}p\to p\pi^0$ and p\eta $ from GlueX experiment using a 9 GeV linearly-polarized, tagged incident on liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as function proton momentum transfer, possess greater precision than previous $\pi^0$ are first $\eta$ this energy regime. results compared with theoretical predictions based $t$-channel, quasi-particle exchange constrain...
The GlueX experiment at Jefferson Lab ran with its first commissioning beam in late 2014 and the spring of 2015. Data were collected on both plastic liquid hydrogen targets, much detector has been commissioned. All systems are now performing or near design specifications events being fully reconstructed, including exclusive production π0, η ω mesons. Linearly-polarized photons successfully produced through coherent bremsstrahlung polarization transfer to ρ observed.
The explicit breaking of the axial symmetry by quantum fluctuations gives rise to so-called anomaly. This phenomenon is solely responsible for decay neutral pion π0 into two photons (γγ), leading its unusually short lifetime. We precisely measured width Γ [Formula: see text] process. differential cross sections photoproduction at forward angles were on targets, carbon-12 and silicon-28, yielding text], where stat. denotes statistical uncertainty syst. systematic uncertainty. combined results...
We present a search for axionlike particles, $a$, produced in photon-proton collisions at center-of-mass energy of approximately 4 GeV, focusing on the scenario where $a$-gluon coupling is dominant. The uses $a\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$ and $a\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$ decays, data sample corresponding to an integrated luminosity $168\text{ }\text{...
Differential cross sections for neutron elastic scattering and inelastic to the first ${2}^{+}$ ${3}^{\mathrm{\ensuremath{-}}}$ excited states have been measured at 10, 14, 17 MeV $^{120}\mathrm{Sn}$ 10 14 $^{116}\mathrm{Sn}$. Analyzing powers also from both isotopes $^{120}\mathrm{Sn}$. These data analyzed in framework of coupled-channels formalism vibrational nuclei. Previously reported measurements performed below 25 MeV, along with total cross-section keV 100 s- p-wave strength functions...
The ($n,2n$) cross section of the radioactive isotope $^{241}\mathrm{Am}$ (${T}_{1/2}=432.6$ y) has been measured in incident neutron energy range from 7.6 to 14.5 MeV steps a few using activation technique. Monoenergetic beams were produced via $^{2}\mathrm{H}$($d,n$)$^{3}\mathrm{He}$ reaction by bombarding pressurized deuterium gas cell with an energetic deuteron beam at TUNL 10-MV Van de Graaff accelerator facility. induced \ensuremath{\gamma}-ray activity $^{240}\mathrm{Am}$ was...
We report on the measurement of beam asymmetry $\mathrm{\ensuremath{\Sigma}}$ for reactions $\stackrel{P\vec}{\ensuremath{\gamma}}p\ensuremath{\rightarrow}p\ensuremath{\eta}$ and $\stackrel{P\vec}{\ensuremath{\gamma}}p\ensuremath{\rightarrow}p{\ensuremath{\eta}}^{\ensuremath{'}}$ from GlueX experiment using an 8.2--8.8-GeV linearly polarized tagged photon incident a liquid hydrogen target in Hall D at Jefferson Laboratory. These measurements are made as function momentum transfer...
Angular distributions of the analyzing power ${A}_{y}$(\ensuremath{\theta}) have been measured for neutron elastic scattering and inelastic to first ${2}_{1}^{+}$ states $^{54}$,56Fe $^{58.60}\mathrm{Ni}$ at 10 MeV, $^{54}\mathrm{Fe}$ $^{58}\mathrm{Ni}$ 14 17 MeV. The differential cross sections \ensuremath{\sigma}(\ensuremath{\theta}) same processes were MeV $^{58}\mathrm{Ni}$. These measurements combined with other also total form a sizable data set incident energies up 80 This has...
The primary motivation of the GlueX experiment is to search for and ultimately study pattern gluonic excitations in meson spectrum produced $γp$ collisions. Recent lattice QCD calculations predict a rich hybrid mesons that have both exotic non-exotic $J^{PC}$, corresponding $q\bar{q}$ states ($q=u,$ $d,$ or $s$) coupled with field. A thorough spectrum, including identification isovector triplet, charges 0 $\pm1$, isoscalar members, $|s\bar{s}\ >$ $|u\bar{u}\ > + |d\bar{d}\ >$, each...
Cross-section measurements of seven exit-channel configurations in the neutron-deuteron breakup at 13.0 MeV are reported and compared to rigorous calculations. Our data consistent with those previous four six configurations. The present for five good agreement theoretical predictions. cross-section space-star another out-of-plane configuration larger than predictions by more three standard deviations. previously observed 20% discrepancy between theory is confirmed work. inclusion...
We report on the measurement of spin density matrix elements $\mathrm{\ensuremath{\Lambda}}(1520)$ in photoproduction reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}(1520){K}^{+}$, via its subsequent decay to ${K}^{\ensuremath{-}}p$. The was performed as part GlueX experimental program Hall D at Jefferson Laboratory using a linearly polarized photon beam with...
New results for the neutron–deuteron analyzing power Ay(θ) at En=1.2 and 1.9 MeV their comparison to proton–deuteron data reveal a sizeable unexpected difference which increases with decreasing center-of-mass energy. This finding calls theoretical treatment of subtle electromagnetic effect presently not incorporated in rigorous three-nucleon scattering calculations, before it is justified invoke charge-dependent forces and/or other new physics.
We propose to enhance the kaon identification capabilities of GlueX detector by constructing an FDIRC (Focusing Detection Internally Reflected Cherenkov) utilizing decommissioned BaBar DIRC components. The would significantly physics program allowing one search for and study hybrid mesons decaying into final states. Such systematic studies states are essential inferring quark flavor content conventional mesons. reuse one-third synthetic fused silica bars that were utilized in DIRC. A new...
We report a measurement of the π− photoproduction beam asymmetry for reaction →γp→π−Δ++ using data from GlueX experiment in photon energy range 8.2–8.8 GeV. The Σ is measured as function four-momentum transfer t to Δ++ and compared phenomenological models. find that varies t: negative at smaller values positive higher |t|. can be described theoretically by t-channel particle exchange requiring pseudoscalar, vector, tensor intermediaries. In particular, this requires charge exchange, allowing...
Measurements of the differential cross sections and analyzing powers have been made for $^{28}$Si(n,${n}_{0}$) $^{28}$Si(n,${n}_{1}$) incident neutron energies between 8 17 MeV. These data combined with previous total cross-section to obtain most complete set scattering from $^{28}\mathrm{Si}$ over 8--40 MeV energy range. The described within framework a symmetric rotational model using phenomenological coupled-channels calculations. Nuclear moments were deduced they are in good agreement...
Neutron cross sections have been measured for 10B and 11B. Elastic angular distribution data are reported incident neutron energies of 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0 MeV. scattering inelastic states at excitation 2.14, 4.46, 5.04 MeV in 11B 9.7, 9.9, Legendre coefficients distributions obtained. All corrected finite geometry multiple effects through a light-element Monte Carlo code. The angle integrated disagreement with ENDF/B-IV the higher energies.
Precision measurements of $^{238}\mathrm{U}$$(n,{n}^{'}\ensuremath{\gamma})$ and $^{238}\mathrm{U}$$(n,2n\ensuremath{\gamma})$ partial cross sections have been performed at Triangle Universities Nuclear Laboratory (TUNL) to improve crucial data needed for testing nuclear reaction models in the actinide mass region. A pulsed monoenergetic neutron beam was used combination with high-resolution \ensuremath{\gamma}-ray spectroscopy obtain incident energies between 5 14 MeV. yields were measured...
The primary motivation of the GlueX experiment is to search for and ultimately study pattern gluonic excitations in meson spectrum produced gamma p collisions. Recent lattice QCD calculations predict a rich hybrid mesons that have both exotic non-exotic JPC, corresponding q q-bar (q=u, d, or s) states coupled with field. A thorough spectrum, including identification isovector triplet, charges 0 +-1, isoscalar members, |s s-bar> |u u-bar> + |d d-bar>, each predicted combination may only be...
Differential cross sections and analyzing powers for neutron elastic scattering from $^{89}\mathrm{Y}$ have been measured at energies 8 to 17 MeV using a time-of-flight facility. The data analyzed with the spherical optical model excellent representations are achieved all derived potential parameters, which were constrained vary linearly energy. Comparisons made two previously reported global models as well.