[Triumf-seminars] TRIUMF Special Seminar today at 14:00
TRIUMF Seminars
triumf-seminars at lists.triumf.ca
Mon Aug 27 05:00:04 PDT 2012
Date/Time: Mon 2012-08-27 at 14:00
Location: Auditorium
Speaker: W. Clark Griffith (Los Alamos National Laboratory)
Title: The search for CP violation in atoms and the neutron
Abstract: Experimental searches for permanent electric dipole moments (EDMs) provide extremely sensitive probes for CP violation beyond the standard model. Atomic EDM searches are sensitive to an electron EDM, or CP violation in the nucleus. The most precise upper bound on an EDM in any system is from the University of Washington atomic mercury experiment. I will discuss the most recent result, which set an upper bound of 3x10-29 e cm on the mercury EDM. The current limit on the neutron EDM is 2.9x10-26 e cm, from an experiment using stored ultracold neutrons (UCN) and an atomic-mercury comagnetometer. While several orders of magnitude less precise than the mercury EDM limit, the neutron EDM result sets comparable bounds on fundamental CP violation compared to mercury because of electron cloud shielding of the mercury nucleus, and the complicated nuclear calculations involved in interpreting the mercury result. Several experiments under development aim to improve neutron EDM sensitivity by one to two orders of magnitude. An experiment to be installed at the Oak Ridge Spallation Neutron Source (SNS) will utilize UCN generated in superfluid helium and a 3^He comagnetometer. I will discuss work on UCN storage cell development for the SNS experiment, and other applications of UCN to fundamental physics measurements.
Stimulants available 15 minutes before the talk.
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