The Status of Inelastic Dark Matter

In light of recent positive results from the DAMA experiment, as well as new null results from CDMS Soudan, Edelweiss, ZEPLIN-I and CRESST, we reexamine the framework of inelastic dark matter with a standard halo. In this framework, which was originally introduced to reconcile tensions between CDMS and DAMA, dark matter particles can scatter off of nuclei only by making a transition to a nearly degenerate state that is roughly 100 \kev heavier. We find that recent data significantly constrains the parameter space of the framework, but that there are still regions consistent with all experimental results. Due to the enhanced annual modulation and dramatically different energy dependence in this scenario, we emphasize the need for greater information on the dates of data taking, and on the energy distribution of signal and background. We also study the specific case of ``mixed sneutrino'' dark matter, and isolate regions of parameter space which are cosmologically interesting for that particular model. A significant improvement in limits by heavy target experiments such as ZEPLIN or CRESST should be able to confirm or exclude the inelastic dark matter scenario in the near future. Within the mixed sneutrino model, an elastic scattering signature should be seen at upcoming germanium experiments, including future results from CDMS Soudan.Comment: 8 pages, 5 figures; updated to include CRESST results; version to appear in Phys.Rev.

Geometry and dynamics of vortex sheets in 3 dimensions

We consider the properties and dynamics of vortex sheets from a geometrical, coordinate-free, perspective. Distribution-valued forms (de Rham currents) are used to represent the fluid velocity and vorticity due to the vortex sheets. The smooth velocities on either side of the sheets are solved in terms of the sheet strengths using the language of double forms. The classical results regarding the continuity of the sheet normal component of the velocity and the conservation of vorticity are exposed in this setting. The formalism is then applied to the case of the self-induced velocity of an isolated vortex sheet. We develop a simplified expression for the sheet velocity in terms of representative curves. Its relevance to the classical Localized Induction Approximation (LIA) to vortex filament dynamics is discusse

Will Expanding Health Care Coverage for People with Disabilities Increase their Employment and Earnings? Evidence from an Analysis of the SSI Work Incentive Program

Reports findings from study that examines the effect that increases in the income threshold under the Supplemental Security Income (SSI) work incentive program have on the employment, earnings, and program participation patterns of SSI recipients. Under Section 1619 of the Social Security Act, SSI recipients may maintain Medicaid eligibility, even if their income is above the level that makes them ineligible for SSI payments. If earnings increase beyond the threshold, however, the person loses their SSI and Medicaid eligibility. Findings indicate that many SSI recipients restrain their earnings to stay below the threshold, supporting the hypothesis that lack of access to health insurance is an important work disincentive for people with disabilities

Exotic Decays of Heavy B quarks

Heavy vector-like quarks of charge $-1/3$, $B$, have been searched for at the LHC through the decays $B\rightarrow bZ,\, bh,\,tW$. In models where the $B$ quark also carries charge under a new gauge group, new decay channels may dominate. We focus on the case where the $B$ is charged under a $U(1)^\prime$ and describe simple models where the dominant decay mode is $B\rightarrow bZ^\prime\rightarrow b (b\bar{b})$. With the inclusion of dark matter such models can explain the excess of gamma rays from the Galactic center. We develop a search strategy for this decay chain and estimate that with integrated luminosity of 300 fb$^{-1}$ the LHC will have the potential to discover both the $B$ and the $Z'$ for $B$ quarks with mass below $\sim 1.6$ TeV, for a broad range of $Z'$ masses. A high-luminosity run can extend this reach to $2$ TeV.Comment: 28 pages, 10 figures, 3 table

Population Status of the Illinois Chorus Frog (Pseudacris Streckeri Illinoensis) in Madison County, Illinois, With Emphasis on the New Poag Road/FAP 413 Interchange and FAP 413 Wetland Mitigation Site. Report on 1993 Results.

IDOT Contract 1-5-90179INHS Technical Report prepared for Illinois Department of Transportatio