R. Kephart
A5068565105- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Particle Accelerators and Free-Electron Lasers
- Dark Matter and Cosmic Phenomena
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Radiation Detection and Scintillator Technologies
- Cosmology and Gravitation Theories
- Neutrino Physics Research
- Atomic and Subatomic Physics Research
- Computational Physics and Python Applications
- Astrophysics and Cosmic Phenomena
- Nuclear physics research studies
- Spacecraft and Cryogenic Technologies
- Nuclear Physics and Applications
- Medical Imaging Techniques and Applications
- Gyrotron and Vacuum Electronics Research
- Black Holes and Theoretical Physics
- Muon and positron interactions and applications
- X-ray Spectroscopy and Fluorescence Analysis
- Physics of Superconductivity and Magnetism
- Radiation Therapy and Dosimetry
- Graphite, nuclear technology, radiation studies
Fermi National Accelerator Laboratory
2012-2022
Iowa State University
2013
University of Pennsylvania
2010
Lawrence Berkeley National Laboratory
2010
Duke University
1994-2009
University of Tsukuba
1982-2009
Purdue University West Lafayette
2009
Fermi Research Alliance
2002-2006
Instituto de Física de Cantabria
2000-2005
Universidad de Cantabria
2000-2005
Dimuon production is studied in 400-GeV proton-nucleus collisions. A strong enhancement observed at 9.5 GeV mass a sample of 9000 dimuon events with ${m}_{{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}}>5$ GeV.
The cross sections for quasielastic electron scattering from nine target nuclei lithium to lead have been measured an incident energy of 500 MeV and a angle 60\ifmmode^\circ\else\textdegree\fi{}. data are interpreted in terms Fermi gas model, yielding the nuclear momentum as function atomic number. increases calcium remains roughly constant at about 260 $\frac{\mathrm{MeV}}{c}$ nickel lead.
We present measurements of the pseudorapidity (η) distribution charged particles (dNchdη) produced within |η|≤3.5 in proton-antiproton collisions at √s 630 and 1800 GeV. measure dNchdη η=0 to be 3.18±0.06(stat)±0.10(syst) GeV, 3.95±0.03 (stat)±0.13(syst) Many systematic errors ratio two energies cancel, we 1.26±0.01±0.04 for GeV that |η|≤3. Comparing lower-energy data, observe an increase faster than ln(s) η=0.Received 2 October 1989DOI:https://doi.org/10.1103/PhysRevD.41.2330©1990 American...
Measurements of inclusive transverse-momentum spectra for charged particles produced in proton-antiproton collisions at √2 630 and 1800 GeV are presented compared with data taken lower energies.Received 8 June 1988DOI:https://doi.org/10.1103/PhysRevLett.61.1819©1988 American Physical Society
We report final results of a series measurements continuum dimuon production in proton-nucleus collisions at Fermilab. New with 6 times more statistics are included. A full description the apparatus and methods used analysis this is given. The sea quark distribution nucleon determined within context Drell-Yan quantum-chromodynamic dilepton hadron collisions.
The mass spectrum of muon pairs in the range 5 to 15 GeV is studied inclusive reaction $p+\mathrm{nucleus}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}+{\ensuremath{\mu}}^{\ensuremath{-}}+\mathrm{anything}$. $\ensuremath{\Upsilon}$ and continuum distribution are presented as $A$ dependence continuum. Comparison with a parton-annihilation model yields sea-quark distribution.
An analysis of pp\ifmmode\bar\else\textasciimacron\fi{} collision events at \ensuremath{\surd}s =1.8 TeV with jets and large missing transverse energy finds no event >40 GeV. This result yields a 90%-C.L. limit on the cross section for one-jet-event production <0.1 nb jet in pseudorapidity range \ensuremath{\Vert}\ensuremath{\eta}\ensuremath{\Vert}<1.0 ${E}_{T}$>52 Limits masses squarks gluinos minimal supersymmetry model are also set. At 90% C.L., ${m}_{q\ifmmode \tilde{}\else...
We present proton-nucleus dimuon-production cross sections for masses between 4 and 15 GeV, center-of-mass rapidities -0.23 0.6 incident energies of 200, 300, 400 GeV. The data confirm scaling to the 20% level. dependence continuum $〈{p}_{T}〉$ on beam energy is also presented.
The production of the $\ensuremath{\Upsilon}$ family in proton-nucleus collisions is clarified by a sixfold increase statistics. Constraining $\ensuremath{\Upsilon}$,${\ensuremath{\Upsilon}}^{\ensuremath{'}}$ masses to those observed at DORIS we find statistical significance ${\ensuremath{\Upsilon}}^{\ensuremath{'}\ensuremath{'}}$ be 11 standard deviations. dependence on ${p}_{t}$, $y$, and $s$ presented. Limits for other resonance mass range 4-18 GeV are determined.
The production of the Jψ resonance in 125-GeV/c p¯ and φ− interactions with Be, Cu, W targets has been measured. cross section per nucleon for is suppressed relative to lighter targets, especially at large values Feynman x, which opposite expectation from various explanations European Muon Collaboration effect. Models incorporating modifications gluon structure functions heavy show qualitative agreement data.Received 14 December 1987DOI:https://doi.org/10.1103/PhysRevLett.60.2121©1988...
We report results on the production of muon pairs in mass range 2.5 to 20 GeV 400-GeV proton-nucleus collisions. A total 159 events are observed 5.5 11 with a cross section which is agreement previous observation high-mass dielectron continuum signal this interval. Details dynamics and comparisons parton-model predictions presented. Within limitations resolution uncertainty, dimuon spectrum provides no evidence for fine structure above 5 GeV.
Inclusive jet production at √s=1.8 TeV has been measured in the CDF detector Fermilab Tevatron ¯pp Collider. Jets with transverse energies (Et) up to 250 GeV have observed. The Et dependence of inclusive cross section is consistent leading-order quantum-chromodynamic calculations, and comparison lower-energy data shows deviations from scaling QCD. A lower limit 700 (95% confidence level) placed on quark compositeness scale parameter Λc associated an effective contact interaction.Received 3...
Fermilab is developing and investigating different high-field magnets (HFM) for present future accelerators. The HFM R&D program focused on the 10-12 T based Nb/sub 3/Sn superconductor explored both basic magnet technologies brittle superconductors-wind-and-react react-and-wind. Magnet design studies in support of LHC upgrades VLHC were conducted. A series 1-m long cos-theta dipole models wind-and-react technique was fabricated tested. Three flat racetracks common coil model, a single-layer...
We have studied muon pairs with an invariant mass between 4 and 9 GeV/c2 produced in p¯N π−N interactions at incident momentum of 125 GeV/c. The experiment was performed Fermilab using a tungsten target special beam enriched to contain 18% antiprotons. compare differential distributions as functions the dimuon mass, Feynman x, transverse momentum, decay angles predictions Drell-Yan model including QCD corrections. Quark structure for p¯ π− are extracted. Comparisons antiproton data...
We have measured the nucleon-number ($A$) dependence of production cross sections for dihadron states in which each hadron is required to large transverse momentum. find that $A$ varies with total momentum a manner similar previously observed single hadrons.
We present the dijet invariant-mass distribution in region between 60 and 500 GeV, measured 1.8-TeV $\overline{p}p$ collisions Collider Detector at Fermilab. Jets are restricted to pseudorapidity interval $|\ensuremath{\eta}|<0.7$. Data compared with QCD calculations; axigluons excluded 95% confidence $120<{M}_{A}<210$ GeV for axigluon width ${\ensuremath{\Gamma}}_{A}=\frac{N{\ensuremath{\alpha}}_{s}{M}_{A}}{6}$, $N=5$.