B. L. Winer

GRB110721A was observed by the Fermi Gamma-ray Space Telescope using its two instruments the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). The burst consisted of one major emission episode which lasted for ~24.5 seconds (in the GBM) and had a peak flux of 5.7\pm0.2 x 10^{-5} erg/s/cm^2. The time-resolved emission spectrum is best modeled with a combination of a Band function and a blackbody spectrum. The peak energy of the Band component was initially 15\pm2 MeV, which is the highest value ever detected in a GRB. This measurement was made possible by combining GBM/BGO data with LAT Low Energy Events to achieve continuous 10--100 MeV coverage. The peak energy later decreased as a power law in time with an index of -1.89\pm0.10. The temperature of the blackbody component also decreased, starting from ~80 keV, and the decay showed a significant break after ~2 seconds. The spectrum provides strong constraints on the standard synchrotron model, indicating that alternative mechanisms may give rise to the emission at these energies.

We investigate the sensitivity of the Gamma-ray Large Area Space Telescope (GLAST) for indirectly detecting weakly interacting massive particles (WIMPs) through the γ-ray signal that their pair annihilation produces. WIMPs are among the favorite candidates for explaining the compelling evidence that about 80% of the mass in the Universe is non-baryonic dark matter (DM). They are serendipitously motivated by various extensions of the standard model of particle physics such as supersymmetry and universal extra dimensions (UED). With its unprecedented sensitivity and its very large energy range (20 MeV to more than 300 GeV) the main instrument on board the GLAST satellite, the Large Area Telescope (LAT), will open a new window of discovery. As our estimates show, the LAT will be able to detect an indirect DM signature for a large class of WIMP models given a cuspy profile for the DM distribution. Using the current state of the art Monte Carlo and event reconstruction software developed within the LAT collaboration, we present preliminary sensitivity studies for several possible sources inside and outside the Galaxy. We also discuss the potential of the LAT to detect UED via the electron/positron channel. Diffuse background modeling and other background issues that will be important in setting limits or seeing a signal are presented.

The Large Area Telescope (LAT) instrument on the Fermi mission will reveal the rich spectral and temporal gamma-ray burst (GRB) phenomena in the >100 MeV band. The synergy with Fermi's Gamma-ray Burst Monitor detectors will link these observations to those in the well explored 10–1000 keV range; the addition of the >100 MeV band observations will resolve theoretical uncertainties about burst emission in both the prompt and afterglow phases. Trigger algorithms will be applied to the LAT data both onboard the spacecraft and on the ground. The sensitivity of these triggers will differ because of the available computing resources onboard and on the ground. Here we present the LAT's burst detection methodologies and the instrument's GRB capabilities.

We report a measurement of the fraction of b quarks produced diffractively in &pmacr;p collisions at sqrt[s] = 1.8 TeV. Diffraction is identified by the absence of particles in a forward pseudorapidity region. From events with an electron of transverse momentum 9.5<p(e)(T)<20 GeV/ c within the pseudorapidity region |eta|<1.1, the ratio of diffractive to total b-quark production rates is found to be R(&bmacr;b) = [0.62+/-0.19(stat)+/-0.16(syst)]%. This result is comparable in magnitude to corresponding ratios for W and dijet production but significantly lower than expectations based on factorization.

Since the spring of 2012 there have been many papers published using Fermi LAT public data that claim evidence for narrow spectral lines coming from the region of the Galactic center. This study uses non-Galactic center Fermi-LAT data from survey mode observations, and Earth limb Fermi data to test the dark matter interpretation of this feature and better understand its origins.

We report on the construction and first operating experience of a novel detector designed to measure with high accuracy the spatial position of charged particle trajectories and of electromagnetic showers from electrons or photons. This position detector was constructed of two layers of 2 mm thick scintillating fibers with a 15° angle between layers. The photon readout used a newly developed multianode photomultiplier. The device was inserted in a prototype electromagnetic calorimeter for the CDF collaboration and studied at a Fermilab test beam facility. The position detector yielded a spatial resolution for electromagnetic showers of 400 μm for 100 GeV electrons.

The Fermi Gamma-Ray Space Telescope was launched in June 2008 and the onboard Large Area Telescope (LAT) has been collecting data since August of that same year. The LAT is currently being used to study a wide range of science topics in high-energy astrophysics, one of which is the study of high-energy cosmic rays. The LAT has recently demonstrated its ability to measure cosmic-ray electrons, and the Fermi LAT Collaboration has published a measurement of the high-energy cosmic-ray electron spectrum in the 20 GeV to 1 TeV energy range. This talk will discuss the prospects for using the LAT to perform a similar analysis to measure cosmic-ray proton events. The instrument response for cosmic-ray protons will be characterized and an assessment of the potential to measure the cosmic-ray proton energy spectrum will be presented.

The CDF II level 1 track trigger system reconstructs charged tracks in the plane transverse to the beam direction. The track trigger electronics uses the hit data from the 4 axial layers of the CDF II central outer tracking chamber, and has been recently upgraded to include the complementary information from the 3 stereo layers. Together with the existing system it provides improved fake track rejection at level 1. In addition, the high resolution segment information is delivered to the Level 2 processors, where software algorithms perform three-dimensional stereo track reconstruction. The 3D-tracks are further extrapolated to the electromagnetic calorimeter towers and muon chambers to generate trigger electron and muon candidates. The invariant mass of track pairs and track isolations are also calculated and used in the level 2 trigger decision. We describe the hardware and software for the level 2 part of the track trigger upgrade as well as the performance of the new track trigger algorithms.

The Fermi Gamma-Ray Space Telescope was launched in June 2008 and the onboard Large Area Telescope (LAT) has been collecting data since August of that same year. The LAT is currently being used to study a wide range of science topics in high-energy astrophysics, one of which is the study of high-energy cosmic rays. The LAT has recently demonstrated its ability to measure cosmic-ray electrons, and the Fermi LAT Collaboration has published a measurement of the high-energy cosmic-ray electron spectrum in the 20 GeV to 1 TeV energy range. Some methods for performing a similar analysis to measure the cosmic-ray proton spectrum using the LAT will be presented with emphasis on unfolding the reconstructed proton energy.

The CDF II eXtremely Fast Tracker (XFT) is a trigger processor which reconstructs charged particle tracks in the transverse plane of the central tracking chamber. The XFT tracks are also extrapolated to the electromagnetic calorimeter and muon chambers to generate trigger electron and muon candidates. The XFT is crucial for the entire CDF II physics program: it detects high Pt lepton from W/Z and heavy flavors decay and, in conjunction with the level 2 processor, it identifies secondary vertices from beauty decay. The XFT has thus been crucial for the recent measurement of the Bs0 oscillation and Σb. The increase of the Tevatron instantaneous luminosity demanded an upgrade of the system to cope with the higher occupancy of the chamber. In the upgraded XFT, three-dimensional tracking reduces the level of fake tracks and measures the longitudinal track parameters, which strongly reinforce the trigger selection. This allows to maintain the trigger perfectly efficient at the record luminosities 2–3×1032cm-2s-1 and to maintain intact the CDF II high luminosity physics program, which includes the Higgs search. In this paper we review the architecture, the used technology, the performance and the impact of the upgraded XFT on the entire CDF II trigger strategy.

Indirect detection of particle dark matter relies upon pair annihilation of Weakly Interaction Massive Particles (WIMPs), which is complementary to the well known techniques of direct detection (WIMP-nucleus scattering) and collider production (WIMP pair production). Pair annihilation of WIMPs results in the production of gamma-rays, neutrinos, and anti-matter. Of the various experiments sensitive to indirect detection of dark matter, the Gamma-ray Large Area Space Telescope (GLAST) may play the most crucial role in the next few years. After launch in 2008, The GLAST Large Area Telescope (LAT) will survey the gamma-ray sky in the energy range of 20 MeV-300 GeV. By eliminating charged particle background above 100 MeV, GLAST may be sensitive to as yet to be observed Milky Way dark matter subhalos, as well as WIMP pair annihilation spectral lines from the Milky Way halo. Discovery of gamma-ray signals from dark matter in the Milky Way would not only demonstrate the particle nature of dark matter; it would also open a new observational window on galactic dark matter substructure. Location of new dark matter sources by GLAST would dramatically alter the experimental landscape; ground based gamma ray telescopes could follow up on the new GLAST sources with precision measurements of the WIMP pair annihilation spectrum.

The GLAST Large Area Telescope (LAT) will measure the cosmic gamma‐ray flux in the energy range 20 MeV to >300 GeV. The LAT will open a new and important window on a wide variety of high‐energy phenomena. Achieving the capability requires a hardware trigger and onboard software event filters that are robust and highly efficient for gamma rays while remaining powerful rejecters of the much larger fluxes of charged‐particle backgrounds. Because of the important discovery windows for science and the uncertainties in the background fluxes, configuration flexibility is a particularly important system feature. This paper describes the purposes and architecture of the system, the components and capabilities of the hardware trigger and onboard software filters, and the on‐orbit operations plan and expected performance.

The CDF II eXtremely Fast Tracker is the trigger track processor which reconstructs charged particle tracks in the transverse plane of the CDF II central outer tracking chamber. The system is now being upgraded to perform a three dimensional track reconstruction. A review of the upgrade is presented here.

The CDF Detector at the Tevatron currently uses an online track trigger, known as the XFT, to identify charged tracks with P/sub T/ > 1.5 GeV/c which are then utilized in a number of ways to produce an event-by-event trigger decision. The tracks found by the XFT are utilized in approximately 80 percent of the physics triggers, including identification of high energy leptons (e, /spl mu/, /spl tau/), events containing heavy, flavor (c, b, t) and events with interesting topologies in for searches for new phenomena. The XFT is functioning well in the current system. As the Tevatron luminosity grows, occupancy in the tracking chamber increases from multiple proton-antiproton interactions. In the trigger, this additional occupancy will cause the tracking resolution to degrade and the rate of fake tracks to grow. We propose to upgrade the existing system to mitigate these effects and allow the CDF detector to operate at its fullest capacity at the highest possible luminosity.

Some of the most affecting moments of this writing came about when women friends, unbidden, offered to be with my children so that I could write.Although I didn't take you up onyour offers, Mary Clifford, Nancy Froehlich, and Madeline Aubrey, I was touched by your kindness.Missing from this list are the many important friends who are also Canadian photographers, writers, and filmmakers, whose works I have been privileged to consider herein.To my son, Dylan, who said to me recently that this book was like another brother or sister he grew up with, and my daughter, Zoe, goes my gratitude for always sharing their mother with this demanding "sibling.