High precision tests of the running of the weak mixing angle with the MOLLER and P2 experiments.

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The experiments we carry out aim to measure the interaction properties between pairs of electrons and quarks down to separation distances of zeptometer (roughly a million times smaller than the size of the smallest atomic nucleus) to unprecedented accuracy. It is widely expected that completely new interactions may be found at such small distances, including those that couple to dark matter, and may explain some of the deepest unanswered questions in particle physics and cosmology (such as the large matter - antimatter asymmetry). The existence of dark matter is the leading explanation for astrophysical phenomena, such as anomalous galactic rotation speeds. The search for dark matter, and new physics that couples to it, is currently at the forefront of the worldwide research effort in subatomic physics. The most innovative aspects of the proposed project are encapsulated in our technical solutions to the extreme challenges involved in making a clean measurement to the proposed accuracy. The MOLLER electron interaction experiment will be a cornerstone of the scientific program at the recently upgraded Thomas Jefferson National Accelerator Facility JLab , a premier electron beam accelerator laboratory located in Newport News, USA, funded by the US Department of Energy (DOE). The experiment is an international effort involving collaborators from the USA and Canada (the lead countries), as well as Germany, Italy, France, and Mexico. The P2 quark interaction experiment is currently under construction at the MESA facility in Mainz, Germany and involves collaborators from Germany, the USA, and Canada. The primary benefits of fundamental research like this are the generation of new knowledge and understanding about nature, the international visibility that high profile efforts like this create for Canada, possible spin-off technologies, and the unique training of highly qualified personnel (HQP) for the technology sector. Some of the needed detector development for these efforts will have a new type of photosensitive readout device that combines modern day microchip technology with precision low noise analog electronics into a single detector unit. These devices could eventually be marketable in the medical diagnostic sector or for personal radiation monitoring. These are large projects with a high capacity for training of HQP from several fields of study beyond physics, including engineering, and computer science. Students and postdocs on this project will acquire a broad set of skills, both on the design and the practical side, including working with sensors, micro-electronics, mechanical assemblies, high vacuum systems, large scale programming, and large data set analysis. These people will have the skill set to be invaluable employees or entrepreneurs in many different sectors, including but not limited to the, information technology, medical, energy, financial, or public sectors.