Light Fields and Their Role in Particle Physics

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This award funds the research activities of Professor Anson Hook at the University of Maryland. This project will advance our knowledge of the fundamental rules of physics underlying nature at the smallest scales. The standard model of particle physics was completed in 2012 with the discovery of the Higgs boson but at the same time made manifest a huge fine tuning problem known as the Electroweak Hierarchy problem. The PI's group will study theories that solve this problem and will explore their experimental implications. A common feature of many of the solutions to the Electroweak Hierarchy problem is the presence of new fundamental particles lighter than any of the other known particles. The PI will work through how new exciting quantum limited experiments as well as astrophysical systems can be used to detect these new particles. This proposal advances the national interest by promoting the progress of fundamental science by discovering and understanding the smallest building blocks of nature. The project will also mentor graduate students and postdocs on research methods as well as helping high school students at local physics competitions.The project will explore and improve upon the solutions to the Hierarchy problem that have been proposed in recent years. The PI will show how non-linearly realized discrete symmetries provide exponential protection of scalar masses and find the guiding rules needed to construct models that utilize this surprising feature. First he will generalize the results of abelian discrete symmetries to non-abelian discrete symmetries. Non-abelian discrete symmetries have accidental symmetries present in some of their interactions in which the Higgs boson can be embedded, extending the exponential protection to the Higgs boson. On the cosmological front, he will study production mechanisms of extremely light vector bosons. By utilizing adiabatic conversion in the presence of a primordial magnetic field, misaligned axions can be turned into vector bosons. This technique can be used to obtain vector dark matter or to reduce the abundance of the axion.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.