ATLAS preparation and exploitation; neutrino physics with T2K, MICE and Neutrino Factory; searches for SUSY dark matter and astrophysical neutrinos

This proposal is directed at exploration of three areas of related new fundamental physics that will help understand better how the Universe was created and why it has the form that we see: (1) Searches with the giant ATLAS detector at CERN (Geneva) for new supersymmetry (SUSY) particles and the Higgs boson: SUSY provides our best theory to explain why the current standard model of particle physics breaks down at high energies, such as would occur in the Big Bang that created the Universe. There is great excitement and anticipation that when ATLAS switches on we will discover and start to understand a whole new spectrum of particles predicted to exist, including the famous Higgs Boson, believed to be the origin of mass, and supersymmetric 'squarks' and 'gluinos'. Our work at Sheffield is focussed now on final construction and testing of the central silicon detector of ATLAS, development of software for measuring particles produced within the experiment and searches for SUSY particles and the Higgs boson with ATLAS data. (2) Searches for new properties of the neutrino produced in accelerators and from space: It is now known that neutrinos are the most common particle in the Universe, that there are three types, that they have very small but different masses, and that the three types can transform (oscillate) from one to another as they pass through space or matter. However, why this is so, what exactly the absolute masses are and how all this impacts on the very structure of matter and the universe is still not certain. Our efforts here focus on two areas: (a) work towards precise measurement of the parameters that govern neutrino oscillation using the upcoming T2K detectors in Japan and eventually a neutrino factory; and (b) work towards searching for high energy neutrinos from space that might tell us more of their properties but also give us new insight into the many very violent astrophysical sources in the Universe, such as active galactic nuclei. For the former we are developing specialist neutrino production targets and new detector technologies for T2K and the neutrino factory based on liquid argon and scintillators. For neutrino astrophysics we are developing novel acoustic and light detection techniques for use in proposed new km-scale deep sea or ice experiments. (3) The search for dark matter: Only 0.5% of the energy-matter content of the Universe is well understood. Of the matter content we know about 80% is non-luminous dark matter most likely composed of a new set of weakly interacting particles created in the Big Bang. There is a world-wide effort to detect these particles, called WIMPs. Working with the ZEPLIN and DRIFT teams, the Sheffield group has built world-leading new detectors underground at Boulby mine based on novel liquid xenon and gas-based technologies. Efforts now are directed at exploiting data from these to search for WIMPs and, with growing numbers of international collaborators, developing much larger ton-scale detectors that can have sensitivity to detect WIMPs with the very smallest predicted capacity to interact with matter. An exciting aspect here is to interpret dark matter results in terms of the new supersymmetry particles relevant to the searches undertaken at ATLAS, and to relate this with the newly emerging properties of the neutrino jointly to improve our whole picture of the structure of the Universe.