R. S. Towell
A5028551047- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Superconducting Materials and Applications
- Nuclear physics research studies
- Nuclear Materials and Properties
- Particle Accelerators and Free-Electron Lasers
- Muon and positron interactions and applications
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Metallurgical Processes and Thermodynamics
- Atomic and Subatomic Physics Research
- Magnetic confinement fusion research
- Molten salt chemistry and electrochemical processes
- Particle accelerators and beam dynamics
- Fungal Infections and Studies
- Radiation Therapy and Dosimetry
- Advancements in PLL and VCO Technologies
- Radioactive Decay and Measurement Techniques
- Semiconductor Lasers and Optical Devices
- Silicon Carbide Semiconductor Technologies
Abilene Christian University
2013-2025
Kurchatov Institute
2023
PHENIX laboratory
2022-2023
Lawrence Livermore National Laboratory
2017-2022
Augustana University
2022
Bhabha Atomic Research Centre
2022
Banaras Hindu University
2022
Stonehill College
2020
High Energy Accelerator Research Organization
2019
National Central University
2019
Measurements of the ratio Drell-Yan yields from an 800 \rm{GeV/c} proton beam incident on liquid hydrogen and deuterium targets are reported. Approximately 360,000 muon pairs remained after all cuts data. From these data, anti-down ($\bar{d}$) to anti-up ($\bar{u}$) quark distributions in sea is determined over a wide range Bjorken-$x$. These results confirm previous measurements by E866 extend them lower $x$. $(\bar{d}-\bar{u})$ $\int(\bar{d}-\bar{u})dx$ evaluated for $0.015<x<0.35$....
A precise measurement of the ratio Drell-Yan yields from an 800GeV/c proton beam incident on hydrogen and deuterium targets is reported. Over 140 000 muon pairs with dimuon mass Mμ+μ−≥4.5GeV/c2 were recorded. From these data, antidown ( d¯) to antiup u¯) quark distributions in sea determined over a wide range Bjorken x. strong x dependence observed d¯/u¯, showing substantial enhancement d¯ respect u¯ for x<0.2. This result fair agreement recent parton distribution parametrizations sea. For...
Measurements of the suppression yield per nucleon J/psi and psi(') production for 800 GeV/ c protons incident on heavy nuclear targets, relative to light have been made with very broad coverage in x(F) p(T). The observed is smallest at values 0.25 below, increases larger x(F). It also strongest small Substantial differences between are first time p-A collisions. stronger than that near zero, but becomes comparable x(F)>0.6.
A precise measurement of the ratios Drell-Yan cross section per nucleon for an 800 GeV/c proton beam incident on Be, Fe, and W targets is reported. The behavior at small target-parton momentum fraction well described by existing fit to shadowing observed in deep-inelastic scattering. cross-section as a function incident-parton set tight limits energy loss quarks passing through cold nucleus.Received 27 May 1999DOI:https://doi.org/10.1103/PhysRevLett.83.2304©1999 American Physical Society
The Drell-Yan cross section ratios, σ(p+d)/σ(p+p), measured in Fermilab E866, have led to the first determination of d¯(x)/ū(x), d¯(x)−ū(x), and integral d¯(x)−ū(x) for proton over range 0.02<~x<~0.345. E866 results are compared with predictions based on parton distribution functions various theoretical models. relationship between NMC measurement Gottfried is discussed. agreement models employing virtual mesons indicates that these non-perturbative processes play an important role origin...
We report a measurement of the angular distributions Drell-Yan dimuons produced using an 800 GeV/c proton beam on deuterium target. The muon in dilepton rest frame have been measured over kinematic range 4.5<m{mu mu}<15 GeV/c{2}, 0<p{T}<4 GeV/c, and 0<x{F}<0.8. No significant cos2phi dependence is found these proton-induced data, contrast with situation for pion-induced data. data are compared expectations from models which attribute distribution to QCD vacuum effect or presence...
We report a measurement of the angular distributions Drell-Yan dimuons produced using an $800\text{ }\text{ }\mathrm{GeV}/c$ proton beam on hydrogen target. The polar and azimuthal distribution parameters have been extracted over kinematic range $4.5<{m}_{\ensuremath{\mu}\ensuremath{\mu}}<15\text{ }\mathrm{GeV}/{c}^{2}$ (excluding $\ensuremath{\Upsilon}$ resonance region), $0<{p}_{T}<4\text{ }\mathrm{GeV}/c$, $0<{x}_{F}<0.8$. $p+p$ are similar to those $p+d$, both data sets...
Fission fragment angular distributions can provide an important constraint on fission theory, improving predictive codes, and are a prerequisite for precise ratio cross section measurement. Available anisotropy data is sparse, especially at neutron energies above 5 MeV. For the first time, three-dimensional tracking detector employed to study emission angles direct measurement of anisotropy. The Neutron Induced Fragment Tracking Experiment (NIFFTE) collaboration has deployed time projection...
The normalized $^{238}$U(n,f)/$^{235}$U(n,f) cross section ratio has been measured using the NIFFTE fission Time Projection Chamber from reaction threshold to $30$~MeV. fissionTPC is a two-volume MICROMEGAS time projection chamber that allows for full three-dimensional reconstruction of fission-fragment ionization profiles neutron-induced fission. measurement was performed at Los Alamos Neutron Science Center, where neutron energy determined time-of-flight. reported here first made with...
The Fermilab E866/NuSea Collaboration has measured the Drell-Yan dimuon cross sections in 800 GeV/$c$ $pp$ and $pd$ collisions. This represents first measurement of section collisions over a broad kinematic region most extensive study to date results indicate that recent global parton distribution fits provide good description light antiquark sea nucleon Bjorken-$x$ range $0.03 \lesssim x < 0.15$, but overestimate valence quark distributions as $x \to 1$.
We present measurements of the polarization J/psi produced in 800-GeV proton interactions with a copper target. Polarization is sensitive to ccmacr; production and hadronization processes. A longitudinal observed at large x(F), while small x(F) state essentially unpolarized or slightly transversely polarized. No significant variation versus p(T).
We present a measurement of the polarization observed for bottomonium states produced in p−Cu collisions at √s=38.8GeV. The angular distribution decay dimuons Υ(1S) state shows no small values fractional longitudinal momentum xF and transverse pT but significant positive production either pT>1.8GeV/c or xF>0.35. Υ(2S+3S) (unresolved) show large all measured. These observations challenge NRQCD calculations expected hadronic states.Received 7 November...
We report a high statistics measurement of $\ensuremath{\Upsilon}$ production with an $800\text{ }\text{ }\mathrm{GeV}/c$ proton beam on hydrogen and deuterium targets. The dominance the gluon-gluon fusion process for at this energy implies that cross section ratio, $\ensuremath{\sigma}(p+d\ensuremath{\rightarrow}\ensuremath{\Upsilon})/2\ensuremath{\sigma}(p+p\ensuremath{\rightarrow}\ensuremath{\Upsilon})$, is sensitive to gluon content in neutron relative proton. Over kinematic region...
The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) collaboration has performed measurements with a fission time projection chamber (fissionTPC) to study the process by reconstructing full three-dimensional tracks of fragments and other ionizing radiation. amount linear momentum imparted fissioning nucleus incident neutron can be inferred measuring opening angle between fragments. Using this measured momentum, fragment angular distributions converted center-of-mass frame for...
The super Pioneering High Energy Nuclear Interaction eXperiment (sPHENIX) at the Relativistic Heavy Ion Collider (RHIC) will perform high precision measurements of jets and heavy flavor observables for a wide selection nuclear collision systems, elucidating microscopic nature strongly interacting matter ranging from nucleons to coupled quark-gluon plasma. A prototype sPHENIX calorimeter system was tested Fermilab Test Beam Facility as experiment T-1044 in spring 2016. electromagnetic (EMCal)...
The SeaQuest spectrometer at Fermilab was designed to detect oppositely-charged pairs of muons (dimuons) produced by interactions between a 120 GeV proton beam and liquid hydrogen, deuterium solid nuclear targets. primary physics program uses the Drell-Yan process probe antiquark distributions in target nucleon. consists system, two dipole magnets four detector stations. upstream magnet is closed-aperture iron which also serves as dump, while second an open aperture magnet. Each stations...