Stephen Peck

Using the Earth as a Polarized Electron Source to Search for Long-Range Spin-Spin Interactions

In Search of Unparticles The standard model of particle physics, which describes the basic building blocks of the universe and the interactions among them, is incomplete. Numerous theoretical extensions have been proposed, some of which predict long-range, spin-spin interactions. To test whether such interactions exist, a laboratory spin source is normally used. Hunter et al. (p. 928) used Earth as a polarized spin source and looked for these interactions by changing the geographical position and the orientation of the measurement apparatus. The polarized spins mainly come from the electrons in iron-containing minerals of Earths mantle, which align in Earths magnetic field. The large numbers of such polarized electrons allowed the extraction of upper bounds on some of the exotic spin-spin interactions far lower than those obtained in the laboratory. Improved bounds on exotic spin-spin interactions were obtained from a study of polarized spins in Earths mantle. Many particle-physics models that extend the standard model predict the existence of long-range spin-spin interactions. We propose an approach that uses the Earth as a polarized spin source to investigate these interactions. Using recent deep-Earth geophysics and geochemistry results, we create a comprehensive map of electron polarization within the Earth induced by the geomagnetic field. We examine possible long-range interactions between these spin-polarized geoelectrons and the spin-polarized electrons and nucleons in three laboratory experiments. By combining our model and the results from these experiments, we establish bounds on torsion gravity and possible long-range spin-spin forces associated with the virtual exchange of either spin-one axial bosons or unparticles.

Limits on local Lorentz invariance in mercury and cesium

We report bounds on local Lorentz invariance (LLI) violation in Cs and Hg. The limits are obtained through the observation of the spin-precession frequencies of

Hyperfine structure of the B3Π1 state and predictions of optical cycling behavior in the X→B transition of TlF

{}^{199}

Prospects for laser cooling TlF

Hg and

Atomic barium and cesium alignment-to-orientation conversion in external electric and magnetic fields

{}^{133}

Using tensor light shifts to measure and cancel a cell's quadrupolar frequency shift

Cs atoms in their ground states as a function of the orientation of an applied magnetic field with respect to the fixed stars. We measure the amplitudes of the dipole couplings to a preferred direction in the equatorial plane to be 19(11) nHz for Hg and 9(5) \ensuremath{\mu}Hz for Cs. The upper bounds established here improve upon previous bounds by about a factor of 4. The improvement is primarily due to mounting the apparatus on a rotating table. Bounds are established on several terms in the standard model extension including the first bounds on the spin couplings of the neutron and proton to the

Hyperfine Structure of the

z

B^3\Pi_1

direction:

State and Predictions of Optical Cycling Behavior in the

{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{b}}_{z}^{n}l7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}30}

X\rightarrow B

GeV and