Measurement of a Lepton Lepton Electroweak Reaction (MOLLER): An Ultraprecise Measurement of the Weak Mixing Angle using Møller Scattering at Jefferson Laboratory

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The discovery of the Higgs boson at CERN was the long-awaited validation of the Standard Model, which summarizes our current understanding of fundamental particles and their interactions. The four fundamental forces are the gravitational, electromagnetic, weak and strong nuclear forces. Ordinary matter consists of a subset of the fundamental particles, electrons and up- and down- quarks bound together as protons and neutrons in the nucleus. The electromagnetic and weak forces have been successfully unified into a quantum electroweak theory, and it is a goal of subatomic theorists to unify the other two forces as well. Despite the success of the Standard Model, it is not complete. Approximately 97% of the matter and energy in the universe is unknown; this "dark" matter and energy is needed to explain the rotation rates of galaxies from astrophysical observations, but is not yet included in the Standard Model. In addition, the two most precise measurements of the weak mixing angle at the mass of the Z boson, which is the mediator of the weak force, do not agree with each other or the measured mass of the Higgs.