UK INVOLVEMENT IN DIRECT DARK MATTER SEARCHES

Future direct dark matter searches will require instruments with improved sensitivity and complementary targets and techniques in order to claim a discovery, and then move to more detailed studies of the particle properties and astrophysical parameters. UK researchers are in an excellent position to participate in the world leading experiments, with significant progress in sensitivity achieved by ZEPLIN-III (liquid xenon target) and EDELWEISS-II (cryogenic germanium), experiments with established UK participation, and with a recent recruitment to the UK bringing a new involvement in DEAP/CLEAN (liquid argon). We anticipate a leading UK role in scale up to a tonne fiducial mass and beyond, probing the majority of the parameter space favoured by the most credible WIMP dark matter models. This proposal focuses on the technical development work necessary to design the EURECA and LUX-ZEPLIN (LZ) experiments, to mitigate technical risks and improving sensitivity. Meeting these goals will also facilitate the positioning of the UK teams for leadership roles in the construction, operation and exploitation of EURECA and LZ.

The technologies being developed are state-of-the-art in terms of particle detection and identification. The detection of WIMPs requires technology which can also detect fast neutrons and even neutrinos. These are of interest to many security-related issues and some developments in this direction to look for neutron production and coherent neutrino-nucleus scattering could follow on. The subject of dark matter scores highly in the public interest. So far the public have followed avidly all the evidence and efforts to make detections, in spite of no credible evidence for discovery yet, but a convincing positive announcement would re-invigorate the interest and doubtless attract young people into following science as a career. For the national funding agencies, a detection would allow a new planning regime with clear and more targeted goals for future studies.