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A new apparatus for a precise comparison of the electron and positron magnetic dipole moments

Shannon Fogwell Hoogerheide '05, Harvard University Ph.D. Student
Thursday, April 28, 2011, 3:45pm, Science Building 101

All known physical laws and processes appear symmetric under the simultaneous inversion of charge (C), parity (P), and time (T). This combination is known as CPT symmetry. A violation of CPT symmetry would indicate the presence of new physics beyond the standard model. A comparison of the electron and positron magnetic moments provides one of the best tests of CPT symmetry. We have recently made the most precise measurement of the electron magnetic moment to date, to an accuracy of 0.28 parts-per-trillion, by observing single quantum transitions of a single, trapped electron. This same technique can easily be extended to positrons, using a different loading mechanism. Using a new, high-stability apparatus, and the same experimental techniques (along with some improvements), we hope to measure the positron (and electron) magnetic moment to an equal or greater precision. This will allow us to make the most precise test of CPT symmetry in a system of leptons, and one of the most precise tests of CPT symmetry in any system.

Note: Hoogerheide has nearly completed her PhD at Harvard under Jerry Gabrielse. Gabrielse spoke at Calvin last month on the group's results for the electron magnetic moment. More from this research group.


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