The Electric Dipole Moment Challenge

With the Higgs particle just confirmed, a remaining blemish of the standard model of elementary particle physics is the excess of particles over antiparticles in the present-day universe, which could be due to the existence of symmetry violation much greater than is currently accepted. Such a symmetry violation would be expected also to imply non-vanishing electric dipole moments (EDMs) for elementary particles such as the proton. Currently, only EDM upper limits have been established. This book explains the "electric dipole moment challenge", which is to measure a non-zero proton EDM value and suggest how the challenge can be met. Any measurably large proton EDM would violate the standard model. The method to be employed uses an intense beam of "frozen spin" protons circulating for hour-long times in a storage ring "trap". It is the smallness of EDMs that allows them to test existing theories, but also what makes them hard to measure. Such EDM experiments are inexpensive, at least compared to building accelerators of ever-greater energy.