Gluonic Excitations and Experimental Hall-D at Jefferson Lab

A new tagged photon beam facility is being constructed in experimental Hall-D at Jefferson Lab as a part of the 12 GeV upgrade program. The 9 GeV linearly-polarized photon beam will be produced via coherent Bremsstrahlung using the CEBAF electron beam, incident on a diamond radiator. The GlueX experiment in Hall-D will use this photon beam to search for and study the pattern of gluonic excitations in the meson spectrum produced through photoproduction reactions with a liquid hydrogen target. Recent lattice QCD calculations predict a rich spectrum of hybrid mesons, that are formed by exciting the gluonic field that couples the quarks. A subset of these hybrid mesons are predicted to have exotic quantum numbers which cannot be formed from a simple $q\bar{q}$ pair, and thus provide an ideal laboratory for testing QCD in the confinement regime. In these proceedings the status of the construction and installation of the GlueX detector will be presented, in addition to simulation results for some reactions of interest in hybrid meson searches.Comment: 5 pages, 4 figures, 1 table, contribution to the proceedings of XXII. International Workshop on Deep-Inelastic Scattering and Related Subjects, 28 Apr - 2 May, 2014, Warsaw, Polan

The STAR W Program at RHIC

The production of $W$ bosons in polarized $p+p$ collisions at RHIC provides an excellent tool to probe the proton's sea quark distributions. At leading order $W^{-(+)}$ bosons are produced in $\bar{u}+d\,(\bar{d}+u)$ collisions, and parity-violating single-spin asymmetries measured in longitudinally polarized $p+p$ collisions give access to the flavor-separated light quark and antiquark helicity distributions. In this proceedings we report preliminary results for the single-spin asymmetry, $A_L$ from data collected in 2012 by the STAR experiment at RHIC with an integrated luminosity of 72 pb$^{-1}$ at $\sqrt{s}=510$ GeV and an average beam polarization of 56%.Comment: Proceedings of the 3rd Workshop on the QCD Structure of the Nucleon (QCD-N' 2012

Liberation of specific angular momentum through radiation and scattering in relativistic black-hole accretion discs

A key component of explaining the array of galaxies observed in the Universe is the feedback of active galactic nuclei, each powered by a massive black hole's accretion disc. For accretion to occur, angular momentum must be lost by that which is accreted. Electromagnetic radiation must offer some respite in this regard, the contribution for which is quantified in this paper, using solely general relativity, under the thin-disc regime. Herein, I calculate extremised situations where photons are entirely responsible for energy removal in the disc and then extend and relate this to the standard relativistic accretion disc outlined by Novikov & Thorne, which includes internal angular-momentum transport. While there is potential for the contribution of angular-momentum removal from photons to be >~1% out to ~10^4 Schwarzschild radii if the disc is irradiated and maximally liberated of angular momentum through inverse Compton scattering, it is more likely of order 10^2 Schwarzschild radii if thermal emission from the disc itself is stronger. The effect of radiation/scattering is stronger near the horizons of fast-spinning black holes, but, ultimately, other mechanisms must drive angular-momentum liberation/transport in accretion discs.Comment: 6 pages, 2 figures. Accepted for publication in PAS

The Impact of Welfare Reform on Leaver Characteristics, Employment and Recidivism: An Analysis of Maryland and Missouri

State and federal reforms of the 1990s transformed the U.S. cash assistance program for single parents and their children. Despite an extensive literature examining these changes and their impacts, there have been few studies that consider the effects of these reforms from the perspective of the recent period. The analysis here focuses on the characteristics and employment of welfare recipients in Maryland and Missouri, 1991-2004. We find that there has been only modest change in the observable characteristics of those entering, remaining on or leaving welfare, but the importance of employment has grown for each of these groups. We also examine the dynamics of employment and welfare recidivism, comparing cohorts of leavers prior to and after welfare reform. We find that after welfare reform leavers are much more likely to be working. Although in Maryland those working have earnings that are somewhat below employed leavers prior to reform, in Missouri earnings for employed leavers are unchanged. In both states, the types of jobs leavers hold have not changed substantially, and leavers are less likely to return to welfare following reform.welfare reform

Tracking and data handling for the pioneer iii and pioneer iv firings

Tracking and data handling systems for Pioneer III space probe and Pioneer IV lunar probe firing

Provisional specification for satellite time in a geomagnetic environment

Satellites in geosynchronous orbit were experiencing operational anomalies. These anomalies are believed to be due to the environment charging the spacecraft surfaces to a point where discharges occur. In designing future satellites for long term operation at geosynchronous altitude, it is important that designers have a specification that will give the total time per year, the particle flux density and particle energies that their satellites can be expected to encounter in these substorm environmental conditions. The limited data currently available on the environmental conditions are used to generate the provisional specification given in this report

Very high voltage latching relay

Relay consists of high voltage reed switch actuated by rotating permanent magnet mounted on stepper motor shaft, with actuation assembly isolated from high voltage circuit. Unit can be modified for use as double pole or double pole double throw latching relay and can be used in either air or vacuum