Spin-Dependent Electron Scattering from Polarized Protons and Deuterons with the BLAST Experiment at MIT-Bates

The Bates Large Acceptance Spectrometer Toroid (BLAST) experiment was operated at the MIT-Bates Linear Accelerator Center from 2003 until 2005. The experiment was designed to exploit the power of a polarized electron beam incident on polarized targets of hydrogen and deuterium to measure, in a systematic manner, the neutron, proton, and deuteron form factors as well as other aspects of the electromagnetic interaction on few-nucleon systems. We briefly describe the experiment, and present and discuss the numerous results obtained.United States. Dept. of EnergyNational Science Foundation (U.S.

A Large Solid Angle Study of Pion Absorption on He3

Measurements have been made of pi+ absorption on He3 at T_pi+ = 118, 162, and 239 MeV using the Large Acceptance Detector System (LADS). The nearly 4pi solid angle coverage of this detector minimizes uncertainties associated with extrapolations over unmeasured regions of phase space. The total absorption cross section is reported. In addition, the total cross section is divided into components in which only two or all three nucleons play a significant role in the process. These are the first direct measurements of the total and three nucleon absorption cross sections.Comment: 8 pages, LaTeX. 3 figures, anonymous ftp MITLNS.MIT.EDU, cd LADS. Submitted to PRL. PSI-PR-94-11 (Paul Scherrer Institute) and LNS 94-56 (MIT Lab. for Nucl. Sci.

Measurement of the proton electric to magnetic form factor ratio from \vec ^1H(\vec e, e'p)

We report the first precision measurement of the proton electric to magnetic form factor ratio from spin-dependent elastic scattering of longitudinally polarized electrons from a polarized hydrogen internal gas target. The measurement was performed at the MIT-Bates South Hall Ring over a range of four-momentum transfer squared $Q^2$ from 0.15 to 0.65 (GeV/c)$^2$. Significantly improved results on the proton electric and magnetic form factors are obtained in combination with previous cross-section data on elastic electron-proton scattering in the same $Q^2$ region.Comment: 4 pages, 2 figures, submitted to PR

Sensitivity of a tonne-scale NEXT detector for neutrinoless double beta decay searches

The Neutrino Experiment with a Xenon TPC (NEXT) searches for the neutrinoless double-beta decay of Xe-136 using high-pressure xenon gas TPCs with electroluminescent amplification. A scaled-up version of this technology with about 1 tonne of enriched xenon could reach in less than 5 years of operation a sensitivity to the half-life of neutrinoless double-beta decay decay better than 1E27 years, improving the current limits by at least one order of magnitude. This prediction is based on a well-understood background model dominated by radiogenic sources. The detector concept presented here represents a first step on a compelling path towards sensitivity to the parameter space defined by the inverted ordering of neutrino masses, and beyond.Comment: 22 pages, 11 figure

Using Q Methodology in Agricultural Communications Research: A Philosophical Study

Communication rests on human experience and the uniqueness of subjectivity. Varying research methods and designs measure subjectivity, but few measure subjectivity using rigorous statistical analysis. Q methodology offers such design and rigor. Yet, agricultural communications has been slow to adopt Q methodology. Therefore, the purpose of this philosophical study was to establish a contextual and philosophical understanding of Q methodology and articulate its uses in agricultural communications research. This philosophical study was without traditional research design and methods. Thus, knowledge gained from the literature and best practices were synthesized with the intent of creating a discussion of the philosophies, concepts, and application of Q methodology. To conduct human subjectivity research, Stephenson proposed Q-methodology. It uses a small number of participants to represent the variance of perspectives about a topic. By focusing on and capturing the holistic perspectives of participants, knowledge bases and understandings of humanistic elements within agricultural communications could be enhanced. Benefits of Q methodology include harnessing subjectivity as a means for testing ideas and characterizing perspectives about an idea, limiting researcher bias, and gaining meaningful data from fewer participants. Challenges include misconceptions and misinterpretations related to terminology, concourse development, and generalizability. Agricultural communications depends on human experience and subjectivity related to food and fiber production. Thus, implementing Q methodology research into the agricultural communications discipline diversifies the research toolbox and provides researchers and practitioners with opportunities to explore perspectives related to diverse agricultural issues

The Charge Form Factor of the Neutron at Low Momentum Transfer from the 2H⃗(e⃗,e′n)p^{2}\vec{\rm H}(\vec{\rm e},{\rm e}'{\rm n}){\rm p} Reaction

We report new measurements of the neutron charge form factor at low momentum transfer using quasielastic electrodisintegration of the deuteron. Longitudinally polarized electrons at an energy of 850 MeV were scattered from an isotopically pure, highly polarized deuterium gas target. The scattered electrons and coincident neutrons were measured by the Bates Large Acceptance Spectrometer Toroid (BLAST) detector. The neutron form factor ratio $G^{n}_{E}/G^{n}_{M}$ was extracted from the beam-target vector asymmetry $A_{ed}^{V}$ at four-momentum transfers $Q^{2}=0.14$, 0.20, 0.29 and 0.42 (GeV/c)$^{2}$.Comment: 5 pages, 3 figures, submitted to Phys. Rev. Let

Studies of di-jet survival and surface emission bias in Au+Au collisions via angular correlations with respect to back-to-back leading hadrons

We report first results from an analysis based on a new multi-hadron correlation technique, exploring jet-medium interactions and di-jet surface emission bias at RHIC. Pairs of back-to-back high transverse momentum hadrons are used for triggers to study associated hadron distributions. In contrast with two- and three-particle correlations with a single trigger with similar kinematic selections, the associated hadron distribution of both trigger sides reveals no modification in either relative pseudo-rapidity or relative azimuthal angle from d+Au to central Au+Au collisions. We determine associated hadron yields and spectra as well as production rates for such correlated back-to-back triggers to gain additional insights on medium properties.Comment: By the STAR Collaboration. 6 pages, 2 figure

Implications For The Origin Of GRB 051103 From LIGO Observations

We present the results of a LIGO search for gravitational waves (GWs) associated with GRB 051103, a short-duration hard-spectrum gamma-ray burst (GRB) whose electromagnetically determined sky position is coincident with the spiral galaxy M81, which is 3.6 Mpc from Earth. Possible progenitors for short-hard GRBs include compact object mergers and soft gamma repeater (SGR) giant flares. A merger progenitor would produce a characteristic GW signal that should be detectable at the distance of M81, while GW emission from an SGR is not expected to be detectable at that distance. We found no evidence of a GW signal associated with GRB 051103. Assuming weakly beamed gamma-ray emission with a jet semi-angle of 30 deg we exclude a binary neutron star merger in M81 as the progenitor with a confidence of 98%. Neutron star-black hole mergers are excluded with > 99% confidence. If the event occurred in M81 our findings support the the hypothesis that GRB 051103 was due to an SGR giant flare, making it the most distant extragalactic magnetar observed to date.Comment: 8 pages, 3 figures. For a repository of data used in the publication, go to: https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=15166 . Also see the announcement for this paper on ligo.org at: http://www.ligo.org/science/Publication-GRB051103/index.ph