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Events in Physics
Title: Using The Earth As A Polarized Electron Source To Search For Long Range Spin-Spin Interactions    (Colloquia)
Start Date: 09/23/2013
Time: 4:15 pm
Location: 1 LeConte Hall
Speaker: Larry Hunter
Affiliation: Professor of Physics, Amherst College
Contact Person: Sarah Wittmer   (510) 642-3034

Many extensions of the standard model of particle physics predict the existence of long-range spin-spin interactions. We have developed an approach which uses the Earth as a polarized spin source to investigate these interactions.  We combine recent deep-Earth geophysics and geochemistry results with precise tabulations of the geomagnetic field to create a comprehensive map of electron polarization within the Earth.  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 new stringent bounds on torsion gravity and possible long-range spin-spin forces associated with the virtual exchange of either spin-one axial bosons or unparticles.  The resulting bound on the spin-spin force between an electron and a neutron is one million times smaller than their gravitational attraction.