537 research outputs found

    How Good a Deal Was the Tobacco Settlement?: Assessing Payments to Massachusetts

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    We estimate the increment in Massachusetts Medicaid program costs attributable to smoking from December 20, 1991, to 1998. We describe how our methods improve upon earlier estimates of analogous costs at the national level. Current costs to the Massachusetts Medicaid program approximate the payments to Massachusetts under the tobacco settlement of November 1998. Whether these payments are viewed as appropriate compensation for Medicaid costs over time depends upon the rate of increase in future health care costs, the rate of decline in smoking, the proportion of smoking that should be attributed to the actions of the tobacco companies and the liklihood that state would have prevailed at trial. The costs to the Medicaid program are dwarfed by the internal costs to smokers themselves.

    Quark Coulomb Interactions and the Mass Difference of Mirror Nuclei

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    We study the Okamoto-Nolen-Schiffer (ONS) anomaly in the binding energy of mirror nuclei at high density by adding a single neutron or proton to a quark gluon plasma. In this high-density limit we find an anomaly equal to two-thirds of the Coulomb exchange energy of a proton. This effect is dominated by quark electromagnetic interactions---rather than by the up-down quark mass difference. At normal density we calculate the Coulomb energy of neutron matter using a string-flip quark model. We find a nonzero Coulomb energy because of the neutron's charged constituents. This effect could make a significant contribution to the ONS anomaly.Comment: 4 pages, 2 figs. sub. to Phys. Rev. Let

    Constraints on Parity-Even Time Reversal Violation in the Nucleon-Nucleon System and Its Connection to Charge Symmetry Breaking

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    Parity-even time reversal violation (TRV) in the nucleon-nucleon interaction is reconsidered. The TRV ρ\rho-exchange interaction on which recent analyses of measurements are based is necessarily also charge-symmetry breaking (CSB). Limits on its strength gˉρ\bar{g}_\rho relative to regular ρ\rho-exchange are extracted from recent CSB experiments in neutron-proton scattering. The result gˉρ6.7×103\bar{g}_\rho\le 6.7\times 10^{-3} (95% CL) is considerably lower than limits inferred from direct TRV tests in nuclear processes. Properties of a1a_1-exchange and limit imposed by the neutron EDM are briefly discussed.Comment: RevTex, 8 pages. Factor ten error in cited neutron EDM corrected, discussion and two references adde

    Seismic Search for Strange Quark Nuggets

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    Bounds on masses and abundances of Strange Quark Nuggets (SQNs) are inferred from a seismic search on Earth. Potential SQN bounds from a possible seismic search on the Moon are reviewed and compared with Earth capabilities. Bounds are derived from the data taken by seismometers implanted on the Moon by the Apollo astronauts. We show that the Apollo data implies that the abundance of SQNs in the region of 10 kg to one ton must be at least an order of magnitude less than would saturate the dark matter in the solar neighborhood.Comment: 7 pages and 4 tables, plus 3 attached figures. Revised version responds to helpful comments of Phys. Rev. referee by adding 3 figures, subtracting two tables and taking into account information from QC

    Measurement of the Absolute np Scattering Differential Cross Section at 194 MeV

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    We describe a double-scattering experiment with a novel tagged neutron beam to measure differential cross sections for np back-scattering to better than 2% absolute precision. The measurement focuses on angles and energies where the cross section magnitude and angle-dependence constrain the charged pion-nucleon coupling constant, but existing data show serious discrepancies among themselves and with energy-dependent partial wave analyses (PWA). The present results are in good accord with the PWA, but deviate systematically from other recent measurements.Comment: 4 pages, 4 figure

    Measurement of the Absolute Differential Cross Section for np Elastic Scattering at 194 MeV

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    A tagged medium-energy neutron beam has been used in a precise measurement of the absolute differential cross section for np back-scattering. The results resolve significant discrepancies within the np database concerning the angular dependence in this regime. The experiment has determined the absolute normalization with 1.5% uncertainty, suitable to verify constraints of supposedly comparable precision that arise from the rest of the database in partial wave analyses. The analysis procedures, especially those associated with evaluation of systematic errors in the experiment, are described in detail so that systematic uncertainties may be included in a reasonable way in subsequent partial wave analysis fits incorporating the present results.Comment: 22 pages, 21 figures, submitted for publication in Physical Review

    Report on CE-19: 16-O(p,n)16-F(0-) in the IUCF Cooler

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    This research was sponsored by the National Science Foundation Grant NSF PHY-931478

    Mirror Dark Matter and Core Density of Galaxies

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    We present a particle physics realization of a recent suggestion by Spergel and Steinhardt that collisional but dissipationless dark matter may resolve the core density problem in dark matter-dominated galaxies such as the dwarf galaxies. The realization is the asymmetric mirror universe model introduced to explain the neutrino puzzles and the microlensing anomaly. The mirror baryons are the dark matter particles with the desired properties. The time scales are right for resolution of the core density problem and formation of mirror stars (MACHOs observed in microlensing experiments). The mass of the region homogenized by Silk damping is between a dwarf and a large galaxy.Comment: 9 pages, LaTex. The present version shows that atomic scattering inherent in the mirror model can solve the core density problem without the need for an extra U(1) discussed in the original version; all conclusions are unchanged. This version is accepted for publication in Phys. Rev.

    New Supernova Constraints on Sterile Neutrino Production

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    We consider the possibility that a light sterile-neutrino species νS\nu_S can be produced by νe\nu_e scattering during the cooling of a proto-neutron star. If we parameterize the sterile neutrino production cross-section by a parameter AA as σ(νeXνSX)=Aσ(νeXνeX)\sigma (\nu_e X\rightarrow \nu_S X) = A \sigma(\nu_e X\rightarrow \nu_e X), where XX is an electron, neutron or proton, we show that AA is constrained by limits to the conversion of νe\nu_e to νS\nu_S in the region between the sterile-neutrino trapping region and the electron-neutrino trapping region. This consideration excludes values of AA in the range between 10^{-4} \la A \la 10^{-1}.Comment: 12 pages; Late
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