The goal of the proposed research and education is to search for dark matter particles in the halo of our galaxy, and to increase the number of female physics students at the University of Florida (UF). The motivation for the search for dark matter comes from our current understanding of the universe. Over the last ten years, a variety of cosmological observations have led to the construction of a concordance model of cosmology. In this very successful model, the universe is made of 4% baryons, which constitute the ordinary matter, 23% nonbaryonic dark matter, which formed all the structures observed today, and 73% dark energy, a smooth component revealed by its effect on the geometry of the universe. Understanding the nature of the dark matter and dark energy are the most important challenges to cosmology. The dark matter could be made of so-called Weakly Interacting Massive Particles (WIMPs), which could have been produced in a very early phase of the universe. These Big Bang relics are particularly interesting because they are also predicted in particle physics theories going beyond the Standard Model of particle physics. They can be detected in the laboratory by searching for nuclear recoils produced when WIMPs scatter off nuclei in a target detector. Because the predicted event rates are very low (smaller than one event per kg detector material and day), and the deposited energies are tiny, massive, ultra-low background experiments are needed in order to detect these hypothetical particles. Liquid xenon has many advantages as a dark matter detector. The high-density and high atomic number allow to build a compact and self-shielded detector, while the simultaneous measurement of the charge and light signal after a WIMP scatters off a Xe-nucleus provides an efficient method to discriminate against background noise from natural radioactivity and cosmic ray interactions. The proposed research has the ultimate goal of building a large liquid Xe dark matter experiment in an underground laboratory. A first, 10 kg liquid Xe dark matter prototype has been approved and will be installed at the Gran Sasso Laboratory in 2006. At the University of Florida, we have built a smaller, 3 kg prototype, with the goal of calibrating the light and charge output of the detector and establishing its discrimination power at low energies by using a neutron beam at the UF tandem accelerator.
The main focus of the educational part of the proposal is to mentor female students in bridging the transition from high school to college and from college to a PhD program on physics. A series of talks will be given at local high schools with the goal of recruiting female students to UF and to a yearly 7 week summer program in which they are actively involved in research in a physics lab. A mentoring program for female undergraduate and graduate students at UF will be established. It will be organized both as small-group tutoring, by pairing one undergraduate and one graduate student and having them meet regularly, as well as in large group activities, such as monthly meetings with a female professor from UF or abroad, and social events. Such meetings, along with office hours for female physics students have been offered since fall 2004, and so far were very well attended. The ultimate goal of the educational component will be to increase the number of women who obtain an advanced degree in physics, and who will continue to have a successful career in science.
