Tests of Fundamental Symmetries Using Spin Magnetometers

University Of Washington, Seattle WA

Investigators

Abstract

This project consists of two experiments aimed at testing fundamental symmetries of nature using spin magnetometers. The first experiment will set new limits on violation of time-reversal symmetry by searching for a permanent Electric Dipole Moment (EDM) using liquid 129-Xe. It will constrain new sources of T and CP violation caused by Supersymmetry and other extensions of the Standard Model. The current best limit on EDM of a diamagnetic atom comes from the 199-Hg experiment and is limited by statistical noise. Using liquid Xe we will be able to increase the number of atoms by eight orders of magnitude and the electric field strength by a factor of 10 relative to the latest version of the 199-Hg experiment. SQUID magnetometers will be used for detection of spin precession and for monitoring leakage currents. The limits on CP violation can be improved by 2 to 4 orders of magnitude. The second experiment will set new limits on CPT violation and Lorentz symmetry violation by comparing the spin precession frequencies of 3-He and 39-K atoms contained in the same cell. CPT and Lorentz symmetry violations can occur in string theories and other theories of quantum gravity. The K magnetometer will operate at low magnetic field and high number density, eliminating relaxation due to spin exchange. We will use a new self-compensating design that takes advantage of the spin-exchange coupling between K and 3-He atoms, while automatically canceling magnetic field fluctuations and eliminating many systematic effects typically limiting atomic spin magnetometers. We expect to improve the existing limits by 2-3 orders of magnitude.