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Fundamental Tests with Antihydrogen Atoms

Friday, March 3, 2017
12:00 PM - 1:00 PM
Location: Watson 104
Joel Fajans, Professor, Department of Physics, University of California, Berkeley

Motivated by the baryogenesis problem (the scarcity of antimatter in the University), CERN's ALPHA collaboration has been studying the properties of antihydrogen atoms.  Since 2010, we have been able to trap nearly 10000 antiatoms, and have kept some trapped for as long as 1000s. We have measured the spin flip frequency of these antiatoms to 0.1%, and the charge of the antiatoms to 0.7ppb; both of these studies search for CPT violations, Just recently,  we were able to determine the 1s-2s transition energy by illuminating antiatoms held within a 243nm laser cavity.  At an accuracy of 200ppt, this is, by some measures, nearly the most precise CPT test ever.   We have also set crude bounds on the gravitational properties of these antiatoms (antimatter g limited by +/-100g), and are constructing a new apparatus designed to measure the antimatter g to 1%; this is a test of the weak equivalence principle. This talk will describe how we trap antihydrogen, and discuss our physics results.


More about the Speaker: Prof. Fajans holds a Ph.D. from Massachusetts Institute of Technology and joined Berkeley faculty in 1988. Awards received include: Hertz Foundation Fellowship, American Physical Society Simon Ramo Thesis Prize, Hertz Foundation Thesis Prize, NSF Presidential Young Investigator Award, ONR Young Investigator Award, Sloan Fellowship, Fellow of the American Physical Society.

Series: Applied Physics Seminar Series
For more information, please phone 626-395-4854 or email

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