584 research outputs found
Asset building: One way the ACA may improve health and employment outcomes for people with disabilities
Working-age individuals with disabilities are often forced to live in poverty to maintain Medicaid coverage. This study
explored the relationship between having assets in excess of usual Medicaid limits and health and quality of life in a sample
of Medicaid Buy-In participants. Using self-reported survey data, we compared groups with US2,000. Participants with higher assets had significantly better health
status and quality of life. Males, younger respondents, and respondents with intellectual disabilities were most likely to have
higher assets. Although many Buy-Ins allow assets greater than US$2,000, assets are still capped for most individuals. The
Affordable Care Act’s Medicaid expansion does not limit assets in determining eligibility. Especially for younger individuals
with disabilities, expansion coverage might allow greater asset accumulation and better health and quality of life, while
avoiding lifelong dependence on disability programs.The author(s) disclosed receipt of the following financial support
for the research, authorship, and/or publication of this article: The
contents of this article were developed under a contract with the
Kansas Department of Health and Environment (KHPA2007-055) and a grant from the U.S. Department of Education, National Institute on Disability and Rehabilitation Research (NIDRR)
Grant H133G100082
Development of high-performance alkali-hybrid polarized He-3 targets for electron scattering
Background: Polarized He-3 targets have been used as effective polarized neutron targets for electron scattering experiments for over twenty years. Over the last ten years, the effective luminosity of polarized He-3 targets based on spin-exchange optical pumping has increased by over an order of magnitude. This has come about because of improvements in commercially-available lasers and an improved understanding of the physics behind the polarization process. Purpose: We present the development of high-performance polarized He-3 targets for use in electron scattering experiments. Improvements in the performance of polarized He-3 targets, target properties, and operating parameters are documented. Methods: We utilize the technique of alkali-hybrid spin-exchange optical pumping to polarize the He-3 targets. Spectrally narrowed diode lasers used for the optical pumping greatly improved the performance. A simulation of the alkali-hybrid spin-exchange optical pumping process was developed to provide guidance in the design of the targets. Data was collected during the characterization of 24 separate glass target cells, each of which was constructed while preparing for one of four experiments at Jefferson Laboratory in Newport News, Virginia. Results: From the data obtained we made determinations of the so-called X-factors that quantify a temperaturedependent and as-yet poorly understood spin-relaxation mechanism that limits the maximum achievable He-3 polarization to well under 100%. The presence of the X-factor spin-relaxation mechanism was clearly evident in our data. Good agreement between the simulation and the actual target performance was obtained by including details such as off-resonant optical pumping. Included in our results is ameasurement of the K-He-3 spin-exchange rate coefficient k(se)(K) = (7.46 +/- 0.62) x 10(-20) cm(3)/s over the temperature range 503 K to 563 K. Conclusions: In order to achieve high performance under the operating conditions described in this paper, the K to Rb alkali vapor density ratio should be about 5 +/- 2 and the line width of the optical pumping lasers should be no more than 0.3 nm. Our measurements of the X-factors under these conditions seem to indicate the He-3 polarization is limited to approximate to 90%. The simulation results, now benchmarked against experimental data, are useful for the design of future targets. Further work is required to better understand the temperature dependence of the X-factor spin-relaxation mechanism and the limitations of our optical pumping simulation
Measurement of Double-Polarization Asymmetries in the Quasielastic (3)(He)over-right-arrow((e)over-right-arrow,e \u27 d) Process
We present a precise measurement of double-polarization asymmetries in the (3)(He) over right arrow((e) over right arrow ,e\u27d) reaction. This particular process is a uniquely sensitive probe of hadron dynamics in He-3 and the structure of the underlying electromagnetic currents. The measurements have been performed in and around quasielastic kinematics at Q(2) = 0.25(GeV/c)(2) for missing momenta up to 270 MeV/c. The asymmetries are in fair agreement with the state-of-the-art calculations in terms of their functional dependencies on p(m) and omega, but are systematically offset. Beyond the region of the quasielastic peak, the discrepancies become even more pronounced. Thus, our measurements have been able to reveal deficiencies in the most sophisticated calculations of the three-body nuclear system, and indicate that further refinement in the treatment of their two-and/or three-body dynamics is required
Moments of the neutron g(2) structure function at intermediate Q(2)
We present new experimental results for the He-3 spin structure function g(2) in the resonance region atQ 2 values between 1.2 and 3.0 (GeV/c)(2). Spin dependent moments of the neutron were extracted. Our main result, the inelastic contribution to the neutron d(2) matrix element, was found to be small at \u3c Q(2)\u3e = 2.4 (GeV/c)(2) and in agreement with the lattice QCD calculation. The Burkhardt-Cottingham sum rule for He-3 and the neutron was tested with the measured data and using the Wandzura-Wilczek relation for the low x unmeasured region
Beam-Target Double-Spin Asymmetry A(LT) in Charged Pion Production from Deep Inelastic Scattering on a Transversely Polarized He-3 Target at 1.4 \u3c Q(2) \u3c 2.7 GeV2
We report the first measurement of the double-spin asymmetry A(LT) for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized He-3 target. The kinematics focused on the valence quark region, 0.16 \u3c x \u3c 0.35 with 1.4 \u3c Q(2) \u3c 2.7 GeV2. The corresponding neutron A(LT) asymmetries were extracted from the measured He-3 asymmetries and proton over He-3 cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function g(1T)(q) and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for pi(-) production on He-3 and the neutron, while our pi(+) asymmetries are consistent with zero
Measurement of pretzelosity asymmetry of charged pion production in semi-inclusive deep inelastic scattering on a polarized He-3 target
An experiment to measure single-spin asymmetries of semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized He-3 target was performed at Jefferson Laboratory in the kinematic region of 0.16 \u3c x \u3c 0.35 and 1.4 \u3c Q(2) \u3c 2.7 GeV2. Pretzelosity asymmetries on He-3, which are expressed as the convolution of the h(1T)(perpendicular to) transverse-momentum-dependent distribution functions and the Collins fragmentation functions in the leading order, were measured for the first time. Under the effective polarization approximation, we extracted the corresponding neutron asymmetries from the measured He-3 asymmetries and cross-section ratios between the proton and He-3. Our results show that both pi(+) on He-3 and on neutron pretzelosity asymmetries are consistent with zero within experimental uncertainties
Double spin asymmetries of inclusive hadron electroproduction from a transversely polarized He-3 target
We report the measurement of beam-target double spin asymmetries (A(LT)) in the inclusive production of identified hadrons, (e) over right arrow + 3He(up arrow) -\u3e h + X, using a longitudinally polarized 5.9-GeV electron beam and a transversely polarized He-3 target. Hadrons (pi(+/-), K-+/-, and proton) were detected at 16 degrees with an average momentum \u3c Ph \u3e = 2.35 GeV/c and a transverse momentum (p(T)) coverage from 0.60 to 0.68 GeV/c. Asymmetries from the He-3 target were observed to be nonzero for pi(+/-) production when the target was polarized transversely in the horizontal plane. The pi(+) and pi(-) asymmetries have opposite signs, analogous to the behavior of A(LT) in semi-inclusive deep-inelastic scattering
Single spin asymmetries in charged kaon production from semi-inclusive deep inelastic scattering on a transversely polarized He-3 target
We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized He-3 target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1 \u3c x(bj) \u3c 0.4 for K+ and K- production. While the Collins and Sivers moments for K+ are consistent with zero within the experimental uncertainties, both moments for K- favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the world data. While the K+ Sivers moments are consistent with the prediction, the K- results differ from the prediction at the 2-sigma level
3He Spin-Dependent Cross Sections and Sum Rules
We present a measurement of the spin-dependent cross sections for the 3→He(→e,e′)X reaction in the quasielastic and resonance regions at a four-momentum transfer 0.1≤Q2≤0.9  GeV2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt-Cottingham and extended Gerasimov-Drell-Hearn sum rules for the first time. The data are also compared to an impulse approximation calculation and an exact three-body Faddeev calculation in the quasielastic region
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