My research focuses on topics at the interface of particle physics, cosmology, and astrophysics. The majority of my work has involved analyzing dark matter direct detection experimental data. I have also analyzed data from indirect detection experiments and used results from the LHC to investigate supersymmetry, especially in the context of dark matter. Some of my newest work has investigated the possibility that non-thermally produced WIMPs could act as an additional source of "dark radiation" hinted at by recent CMB experiments.
My most recent project in direct detection examined the effects of including baryonic physics in N-body simulations of galaxy formation. Results from direct detection experiments are often analyzed assuming a simple isothermal distribution of dark matter, the Standard Halo Model (SHM). In this project we compared the SHM to the results of cosmological hydrodynamical simulations of galaxy formation to investigate whether or not the SHM is a good representation of the true WIMP distribution in the analysis of direct detection data. We found that in the Solar neighborhood, the SHM is in fact a good approximation to the true dark matter distribution in these cosmological simulations (with baryons) which are reasonable representations of the Milky Way, and hence can also be used for the purpose of dark matter direct detection calculations.
A major scientific mission of the Fermi Gamma-Ray Space Telescope is the search for gamma-rays from dark matter annihilations. I have analyzed the publicly available Fermi data in the region of the Galactic center to derive what were the strongest limits on dark matter annihilation. With the arrival of Dr. Hewitt to UNF an expert member of the Fermi Collaboration, I am very excited work with Dr. Hewitt and UNF students analyzing Fermi data.
Collider SearchesI have also been working on dark matter within the framework of supersymmetry. In a recent project we looked at the possibility of light sleptons with left-right mixing still allowed by the LHC and their implications for the relic density of dark matter along with the dipole moment contraints for these models. We showed that the sleptons could make neutralino annihilation efficient enough to lower the relic density (shown as the black contours in the figure) into the allowed range (less than 0.12). The red region shows where the anomalous magnetic moment of the muon could be explained in this scenario. We have also been looking at models with a light squark so that the dominant direct detection signal would come from this charged mediator. We are extending this work to determine if mixing within the squark sector could allow light squarks to provide a co-annihilation mechanism for getting the correct relic density.
Curriculum Vitae You can view my current CV as a pdf.