Assessment of the Science Proposed for the Deep Underground Science and Engineering Laboratory (DUSEL)

摘要

Underground laboratories are a relatively new kind of research facility, developed primarily because they provide the extremely quiet environment needed to study rare events such as proton decay and the faint signals associated with neutrinosghostly particles with very little mass and no net charge that only weakly engage with most normal matter. As weak or rare as those signals are, their study will have profound implications; breakthroughs in any of the leading physics experiments that study these signals will be the foundations upon which a significant portion of the physics community builds for decades to come. Because of the importance of these studies, a number of underground research facilities have been built around the world, including a modest facility in the United States. Led by the National Science Foundation (NSF) and working in conjunction with the Department of Energy (DOE), the research communities that engage in underground science in the United States developed an integrated research program centered around a major underground facility to be located in South Dakota: the Deep Underground Science and Engineering Laboratory (DUSEL). As part of the process of developing DUSEL and the program associated with it, NSF and DOE jointly commissioned this study. The principal charge to the committee was to independently assess the physics questions that could be addressed with the proposed program, how such a program would impact the stewardship of the research communities involved, and whether there was a need to develop such a program in the United States, given similar science programs elsewhere. The committee also was charged with assessing the potential impact of this facility on research in nonphysics fields and on broader interests such as education and public outreach. In response to this charge, the committee concludes that three of the proposed physics experiments(1) a direct detection dark matter experiment on a scale of one to tens of tons, (2) a long-baseline neutrino oscillation experiment, and (3) a ton-scale, neutrinoless double-beta decay experimentare of paramount and comparable scientific importance. Each of these experiments addresses at least one crucial question upon which the tenets of our understanding of the Universe depend.