J. R. Bogart
A5064589795- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Particle Accelerators and Free-Electron Lasers
- Neutrino Physics Research
- Advanced Data Storage Technologies
- Astronomy and Astrophysical Research
- Particle accelerators and beam dynamics
- Atomic and Subatomic Physics Research
- Computational Physics and Python Applications
- Astronomical Observations and Instrumentation
- Nuclear physics research studies
- Nuclear Physics and Applications
- Big Data Technologies and Applications
- Radio Astronomy Observations and Technology
- Medical Imaging Techniques and Applications
- Photocathodes and Microchannel Plates
- Atomic and Molecular Physics
- Image Processing and 3D Reconstruction
- Mathematics, Computing, and Information Processing
- Distributed and Parallel Computing Systems
SLAC National Accelerator Laboratory
2005-2024
Menlo School
2002-2022
Kavli Institute for Particle Astrophysics and Cosmology
2009-2021
Stanford University
2003-2021
Stockholm University
2009
Stanford Synchrotron Radiation Lightsource
1995-2005
Linac Coherent Light Source
2002
Aomori University
2002
Adelphi University
1997-2000
Campbell Collaboration
1997
(Abridged) The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on Fermi Gamma-ray Space (Fermi) mission, is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering energy range from below 20 MeV to more than 300 GeV. This paper describes LAT, its pre-flight expected performance, and summarizes key science objectives that will be addressed. On-orbit performance presented in detail a subsequent paper. LAT pair-conversion telescope with precision...
(Abridged) We describe here the most ambitious survey currently planned in optical, Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST have unique capability faint time domain. The design is driven four main themes: probing dark energy matter, taking an inventory Solar System, exploring transient optical sky, mapping Milky Way. wide-field ground-based system sited at Cerro Pach\'{o}n northern Chile. telescope 8.4 m...
We present the third Fermi Large Area Telescope (LAT) source catalog (3FGL) of sources in 100 MeV–300 GeV range. Based on first 4 yr science data from Gamma-ray Space mission, it is deepest yet this energy Relative to Second LAT catalog, 3FGL incorporates twice as much data, well a number analysis improvements, including improved calibrations at event reconstruction level, an updated model for Galactic diffuse γ-ray emission, refined procedure detection, and methods associating with...
Gamma-ray bursts (GRBs) are highly energetic explosions signaling the death of massive stars in distant galaxies. The Burst Monitor and Large Area Telescope onboard Fermi Observatory together record GRBs over a broad energy range spanning about 7 decades gammaray energy. In September 2008, observed exceptionally luminous GRB 080916C, with largest apparent release yet measured. high-energy gamma rays to start later persist longer than lower photons. A simple spectral form fits entire...
The Fermi Large Area Telescope (Fermi-LAT, hereafter LAT), the primary instrument on Gamma-ray Space (Fermi) mission, is an imaging, wide field-of-view, high-energy γ-ray telescope, covering energy range from 20 MeV to more than 300 GeV. During first years of LAT team has gained considerable insight into in-flight performance instrument. Accordingly, we have updated analysis used reduce data for public release as well response functions (IRFs), description provided analysis. In this paper,...
We present the first catalog of active galactic nuclei (AGNs) detected by Large Area Telescope (LAT), corresponding to 11 months data collected in scientific operation mode. The First LAT AGN Catalog (1LAC) includes 671 γ-ray sources located at high Galactic latitudes (|b|>10°) that are with a test statistic greater than 25 and associated statistically AGNs. Some multiple AGNs, consequently, 709 comprising 300 BL Lacertae objects, 296 flat-spectrum radio quasars, 41 AGNs other types, 72...
We present the results of our analysis cosmic-ray electrons using about $8\ifmmode\times\else\texttimes\fi{}{10}^{6}$ electron candidates detected in first 12 months on-orbit by Fermi Large Area Telescope. This work extends previously published spectrum down to 7 GeV, giving a spectral range approximately 2.5 decades up 1 TeV. describe detail and its validation beam-test data. In addition, we measured via subset events selected for best energy resolution as cross-check on measurement full...
The Vela pulsar is the brightest persistent source in GeV sky and thus traditional first target for new gamma-ray observatories. We report here on initial Fermi Large Area Telescope observations during verification phase pointed exposure early survey scanning. have used signal to verify timing angular resolution. high quality pulse profile, with some 32,400 pulsed photons at E>0.03 GeV, shows features, including structure as fine 0.3ms a distinct third peak, which shifts energy. examine...
Abstract We describe the simulated sky survey underlying second data challenge (DC2) carried out in preparation for analysis of Vera C. Rubin Observatory Legacy Survey Space and Time (LSST) by LSST Dark Energy Science Collaboration (LSST DESC). Significant connections across multiple science domains will be a hallmark LSST; DC2 program represents unique modeling effort that stresses this interconnectivity way has not been attempted before. This encompasses full end-to-end approach: starting...
Abstract The Vera Rubin Observatory Legacy Survey of Space and Time (LSST) is expected to process ∼10 6 transient detections per night. For precision measurements cosmological parameters rates, it critical understand the detection efficiency, magnitude limits, artifact contamination levels, biases in selection photometry. Here we rigorously test LSST Difference Image Analysis (DIA) pipeline using simulated images from Dark Energy Science Collaboration Data Challenge (DC2) simulation for...
We present a precise measurement of the left-right cross section asymmetry (${A}_{\mathrm{LR}}$) for $Z$ boson production by ${e}^{+}{e}^{\ensuremath{-}}$ collisions. The was performed at center-of-mass energy 91.26 GeV with SLD detector SLAC Linear Collider (SLC). luminosity-weighted average polarization SLC electron beam (63.0 \ifmmode\pm\else\textpm\fi{} 1.1)%. Using sample 49 392 decays, we measure ${A}_{\mathrm{LR}}$ to be 0.1628 0.0071 (stat) 0.0028 (syst) which determines effective...
We present a measurement of the b-quark inclusive fragmentation function in ${Z}^{0}$ decays using novel kinematic B-hadron energy reconstruction technique. The was performed 350 000 hadronic events recorded SLD experiment at SLAC between 1997 and 1998. small stable SLC beam spot charge-coupled-device--based vertex detector were used to reconstruct B-decay vertices with high efficiency purity, provide precise measurements quantities this measured B good resolution over full range. compared...
The OpenUniverse2024 simulation suite is a cross-collaboration effort to produce matched simulated imaging for multiple surveys as they would observe common sky. Both the data and associated tools used it are intended uniquely enable wide range of studies maximize science potential next generation cosmological surveys. We have produced approximately 70 deg$^2$ Vera C. Rubin Observatory Legacy Survey Space Time (LSST) Wide-Fast-Deep survey Nancy Grace Roman Telescope High-Latitude Wide-Area...
The strong coupling αs(M2Z) has been measured using hadronic decays of Z0 bosons collected by the SLD experiment at SLAC. data were compared with QCD predictions both fixed order O(α2s) and including resummed analytic formulas based on next-to-leading logarithm approximation. In this comprehensive analysis we studied event shapes, jet rates, particle correlations, angular energy flow, checked consistency between values extracted from these different measures. Combining all results obtain...
We present measurements of ${\mathit{R}}_{\mathit{b}}$ using the SLD at SLC. The analyses use 2D and 3D impact parameter tags a displaced vertex tag which all exploit small size stability ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ interaction point precision CCD pixel detector to achieve high bb\ifmmode\bar\else\textasciimacron\fi{}-tagging efficiencies purities. combined measurement yields ${\mathit{R}}_{\mathit{b}}$=0.229\ifmmode\pm\else\textpm\fi{}0.011 is consistent with...
We present a measurement of the left-right cross-section asymmetry ( A(LR)) for Z boson production by e(+)e(-) collisions. The includes final data taken with SLD detector at SLAC Linear Collider during period 1996-1998. Using sample 383 487 decays collected 1996-1998 runs we measure pole value asymmetry, A(0)(LR), to be 0.150 56+/-0.002 39 which is equivalent an effective weak mixing angle sin (2)straight theta(eff)(W) = 0.231 07+/-0.000 30. Our result complete 1992-1998 set comprising...
We present improved measurements of the differential production rates stable charged particles in hadronic Z0 decays, and pions, kaons protons identified over a wide momentum range using SLD Cherenkov Ring Imaging Detector. In addition to flavor-inclusive are made for decays into light (u, d, s), c b primary flavors, selected upgraded Vertex Large differences between flavors observed that qualitatively consistent with expectations based upon previously measured decay properties heavy...
We present the first measurement of left-right cross section asymmetry (${\mathit{A}}_{\mathit{L}\mathit{R}}$) for Z boson production by ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ collisions. The was performed at a center-of-mass energy 91.55 GeV with SLD detector SLAC Linear Collider which utilized longitudinally polarized electron beam. average beam polarization (22.4\ifmmode\pm\else\textpm\fi{}0.6)%. Using sample 10 224 decays, we measure...
We have developed a new technique for inclusive reconstruction of the energy B hadrons. The excellent efficiency and resolution this allow us to make most precise determination b-quark fragmentation function, using e(+)e(-)-->Z0 decays recorded in SLAC Large Detector experiment. compared our measurement with predictions number models. excluded several these models measured average scaled weakly decaying hadrons be <x(B)> = 0.714+/-0. 005(stat)+/-0.007(syst)+/-0.002 (model dependence).
We report a new measurement of Rb = Gamma(Z0->b-bbar) / Gamma(Z0->hadrons) using double tag technique, where the b hemisphere selection is based on reconstructed mass B hadron decay vertex. The was performed sample 130k hadronic Z0 events, collected with SLD at SLC. method utilizes 3-D vertexing abilities CCD pixel vertex detector and small stable SLC beams to obtain high b-tagging efficiency purity. Rb=0.2142+/-0.0034(stat.)+/-0.0015(syst.)+/-0.0002(R_c).