Dark matter research is at an exciting juncture. The confluence of increasingly sensitive direct detection experiments, large indirect detection experiments, the discovery of more local group galaxies and the Large Hadron Collider is likely to dramatically broaden our understanding of dark matter in the next few years. The PI proposes to undertake novel investigations that deal with the collisionless and collisional aspects of dark matter including indirect detection of dark matter and coupling of dark matter and dark energy. The PI will also investigate how strong gravitational lensing data sets made available by future large sky surveys may be used to study dark energy. The PI will also investigate constraints from Big Bang Nucleosynthesis (BBN) on a large class of beyond standard model theories that have charged particles that decay during or after BBN. The education and outreach plan of this program is focused on the UC Irvine Physics Road Show program. The Road Show takes basic physics demonstrations, presented by UCI undergraduates, to an ethnically and economically diverse group of elementary and middle school students in schools in the neighboring districts.
This grant has funded work on astrophysics, particle astrophysics and cosmology. The work can be broadly divided into dark matter content of small galaxies, dark matter models and neutrino mass. The dark matter content of small galaxies is important because we may be able to distinguish different models of dark matter based on their predictions for these small galaxies. The work funded partially through this grant led to the identification of the least luminous galaxy known and a better understanding of the amount of dark matter in these small galaxies. The dark matter content of is of importance in efforts to look for non-gravitational signatures of dark matter in the sky. Our work on dark matter models has disfavored large classes of dark matter models that were among the most favored candidates. Our work also highlighted the possibility that the dark matter while weakly coupled to normal matter could strongly interact with itself. More detailed investigations (since the papers funded by this grant) seem to show that this possibility is attractive because it may explain some long-standing issues related to the density of dark matter in the central parts of small galaxies. Masses of the three known neutrinos are the only unknown parameters in the standard model of particle physics. It may be possible to measure the sum of these masses using measures of the large-scale structure of the Universe and its evolution. The work funded by this grant will hopefully be useful for the next generation experiments in cosmology that are aiming to better understand dark energy and simultaneously measure the sum of neutrino masses.
