Preferred-Frame and CP-Violation Tests with Polarized Electrons

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We used a torsion pendulum containing ≈ 10²³ polarized electrons to search new interactions that couple to electron spin. We limit CP-violating interactions between the pendulum's electrons and unpolarized matter in the earth or the sun, test for rotation and boost-dependent preferred-frame effects using the earth's rotation and velocity with respect to the entire cosmos, and search for exotic velocity-dependent potentials between polarized electrons and unpolarized matter in the sun and moon. Finally, we find that the gravitational mass of an electron spinning toward the galactic center differs by less than about 1 part in 10²¹ from an electron spinning in the opposite direction. As a byproduct of this work, the density of polarized electrons in Sm Co₅ was measured to be (4.19± 0.19)× 10²² cm⁻³ at a field of 9.6 kG.