310 likes | 442 Views
Search for the Electron Electric Dipole Moment. Experiment: D.DeMille, D. Kawall, R.Paolino, V. Prasad F. Bay, S. Bickman, P.Hamilton, Y. Jiang, Y.Gurevich Yale University L.R.Hunter (Amherst) Theory: M. Kozlov ( PNPI, St. Petersburg) , D. DeMille. Val Prasad Yale University. D. S.
E N D
Search for the Electron Electric Dipole Moment Experiment: D.DeMille, D. Kawall, R.Paolino, V. Prasad F. Bay, S. Bickman, P.Hamilton, Y. Jiang, Y.Gurevich Yale University L.R.Hunter (Amherst) Theory: M. Kozlov (PNPI, St. Petersburg), D. DeMille Val Prasad Yale University
D S An EDM Violates Parity and Time Reversal Symmetries and may provide evidence of new physics P T look different after P reversal look different after T reversal T-violation: a window to new physics CPT theorem T-violation = CP-violation
e e Feynman Diagram not renormalizable loop diagrams
Theoretical Predictions for de NAIVESUSY HsF M-H AC Align A-CP A-Un LR-S L-FC E-Un TC YaleI (projected) Yale II(projected) Berkeley SO(10) GUT StdModel 10-26 10-30 10-28 10-32 10-40 de (e·cm) Experimental limit: |de| < 1.610-27 ecm (Berkeley)
B General Method to Detect an EDM E spin Energy Shift Resolution ~____(de.Eeff)_______ (Tcoh .√(dN/dt Tmeas))-1
Schiff’s theorem Cannot apply an electric field to a free electron for long times Use a neutral object (atoms, molecules) Near nucleus, v, E, large + substantial amplitude for valence e-: r ~ a0/Z; v ~ Zc; E ~ Ze/r2; B ~ea0; (0) ~Z1/2 |<Eeff>| Z32 (e/a02) P
Molecules enhance electric fields Atoms • Large laboratory fields ~50 kV/cm • Leakage currents=BAD!!! • Smaller enhancement factors O E Eext~10 V/cm Eint~1010 V/cm Pb Molecules • Unpaired electron=free radical • Boltzmann distribution over many rovibrational states M. G. Kozlov and D. DeMillePhys. Rev. Lett. 89, 133001 (2002)
=0 =-1 =+1 =1 states coupled in 2nd order via molecular rotation (Coriolis) E ~ (Erot)2/Est ~ 10-3Erot Symmetric-antisymmmetric states split by tunneling An aside: what’s an -doublet? Non-rotating molecule has internal tensor Stark shift
Thallium vs PbO* PbO*: ΔEedm = 2.5 x 1025 Hz x de (e-cm)
Excitation scheme 2+ 2- X(0)[1Σ+] 1- 1+ ~12 MHz a(1) [3 Σ+] 2+ Laser pulse λ~571 nm t~10 ns Bandwidth~1GHz~ΔνDoppler R0208Pb J’’=0→J’=1 1- ~10 GHz 0+
X(v’’ = 1) a(v’ = 5) excitation ( = 571 nm) a(v’ = 5) X(v’’ = 0) detection ( = 548 nm) Integrated over ~200 s after each pulse Integrated intensity R0(J”=0J’=1-) 208Pb Tune laser here Molecular Spectra
Omega Doublet ν~11.2 MHz νZeeman~300 kHz m=0 m=-1 m=1 E =0 B =0
Excitation Scheme RF pulse B E
Excitation Scheme RF pulse B E
Excitation Scheme B E RF pulse
Quantum Beats • Coherent superposition of two states decaying to the same state • Precession frequency proportional to energy difference between states • Allows for Doppler free, very precise spectroscopy (<1mHz) y x
Systematics Considerations • Motional Magnetic Fields • Magnetic Noise • Leakage Currents • Multi-photon ionization • E-field gradients • Inhomogeneities in E-field • Stray B-fields and E-fields
g-factor measurement To what extent is the - doublet a perfect mirror image? -doublet useful as Co-Magnetometer Results help constrain calculation of enhancement-factor
Typical Data Averaged over 0.5 s, Bz~60 mG
Omega Doublet ν~11.2 MHz νZeeman~300 kHz m=0 m=-1 m=1 E =0 B =0
Conclusions • Many preliminary steps have been successfully demonstrated • Improvements in excitation and detection efficiencies look promising • Attacking a few remaining experimental issues before we take a first look at the data …………….