New CP-violation and preferred-frame tests with polarized electrons

We used a torsion pendulum containing \(\sim 9 \times 10^{22}\) polarized electrons to search for CP-violating interactions between the pendulum's electrons and unpolarized matter in the laboratory's surroundings or the sun, and to test for preferred-frame effects that would precess the electrons about a direction fixed in inertial space. We find \(|g_{\rm P}^e g_{\rm S}^N|/(\hbar c)< 1.7 \times 10^{-36}\) and \(|g_{\rm A}^e g_{\rm V}^N|/(\hbar c) < 4.8 \times 10^{-56}\) for \(\lambda > 1\)AU. Our preferred-frame constraints, interpreted in the Kostelecký framework, set an upper limit on the parameter \(|\bm{\tilde {b}}^e| \leq 5.0 \times 10^{-21}\) eV that should be compared to the benchmark value \(m_e^2/M_{\rm Planck}= 2 \times 10^{-17}\) eV.