#1 “New” ILL EDM Experiment Systematic Comment on “An Improved Experimental Limit on the Electric-Dipole Moment of the Neutron,” C.A. Baker, et al. [1] S.K. Lamoreaux Yale University R. Golub North Carolina State University

#2 ILL Experiment 1 UCN/cc 10 kV/cm 120 sec store 1.5 x e cm 199 Hg Co-magnetometer—Systematic control A new systematic “geometric phase” effect was found in this work (controllable at the e cm level for our experiment)

#3 Gradient interference with E x v field Radial gradient v x E field Changes sign with direction

#4 Monte Carlo calculation of shift

#5 Change in apparent ratio of gyromagnetic ratios is used to determine the gradient The gradient thus determined is used to evaluate the geometric phase systematic effect A comparison between magnetic field “up” vs. field “down” allows extraction of the true EDM Any effect that causes a shift in the ratio of gyromagnetic ratios that depends on the magnetic field direction will cause a systematic effect

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#10 Result of line intersection in [1]

#11 Two Versions of Systematic Effects c.f due to Earth rotation originalfinal

#12 The systematic error appears as underestimated