Deep Underground Science and Engineering Lab Dark Matter Working Group 2007

This whitepaper is the result of discussions and presentations initiated at the DUSEL Town Meeting held in Washington in November 2007. The essential elements of this report are: • The quest to detect dark matter is a science goal of the very highest priority, and is flagship science for DUSEL. • The dark matter community presents here a Roadmap for a set of proposals for the Initial Suite of Experiments. The science goals will be reached in two phases of experiments, at the 4850 and 7400 ft levels, respectively. • The US is currently the world leader in the search for WIMP dark matter. Constructing DUSEL will ensure that the US will continue its leading role and attract international collaborators to DUSEL. The discovery of dark matter is of fundamental importance to cosmology, astrophysics, and elementary particle physics [1, 2, 3, 4, 5]. 1 A broad range of observations from the rotation speed of stars in ordinary galaxies to the gravitational lensing of superclusters tell us that 80–90% of the matter in the universe is in some new form, different from ordinary particles, that does not emit or absorb light. Cosmological observations, especially the Wilkinson Anisotropy Probe of the cosmic microwave background radiation, have provided spectacular confirmation of the as-trophysical evidence. The resulting picture, the so-called " Standard Cosmology, " finds that a quarter of the energy density of the universe is dark matter and most of the remainder is dark energy. A basic foundation of the model, Big Bang Nucleosynthesis (BBN), tells us that at most about 5% is made of ordinary matter, or baryons. The solution to this " dark matter problem " may therefore lie in the existence of some new form of non-baryonic matter. With ideas on these new forms coming from elementary particle physics, the solution is likely to have broad and profound implications for cosmology, astrophysics, and fundamental interactions. While non-baryonic dark matter is a key component of the cosmos and the most abundant form of matter in the Universe, so far it has revealed itself only through gravi-tational effects—determining its nature is one of the greatest scientific issues of our time, making the potential for its discovery and study a key program at DUSEL. Many potential new forms of matter have been suggested as dark matter candidates in theories that go beyond the Standard Model of strong and electroweak interactions, but none has …