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Test of fundamental symmetries

Test of fundamental symmetries. from an atomic physics perspective. With thanks to Antoine Weis. Mike Tarbutt. Sumerian, 2600 B.C. (British Museum). CPT theorem. Time-reversal T. Charge conjugation C. Parity P. Combine. CPT.

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Test of fundamental symmetries

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  1. Test of fundamental symmetries from an atomic physics perspective With thanks to Antoine Weis Mike Tarbutt Sumerian, 2600 B.C. (British Museum)

  2. CPT theorem Time-reversal T Charge conjugation C Parity P Combine CPT All local, Lorentz-invariant quantum field theories are invariant under CPT

  3. CP & T violation CP violation T violation 1964 – CP violation observed in decays of neutral K-mesons 1998 – T violation observed in decays of neutral K-mesons 2001 – CP violation observed in decays of neutral B-mesons Consistent with Standard Model CPT theorem Our solar system – 2 billion billionbillion tonnes of matter Our galaxy – 200 billion stars Observable universe – 80 billion galaxies

  4. How to measure T-violation T E B - - - - + + + + - - - - - - - - + + + + - - - - + + + + E + + + + E B B B E P E.B is T-odd AND P-odd Gives us an apparatus to measure T-odd (and P-odd) properties

  5. Particle EDM’s, the Standard Model & beyond - 10-22 Spin Spin + Edm Edm 10-24 MSSM f ~ 1 10-26 Multi Higgs Left -Right Either de = 0, or T MSSM f ~ a/p 10-28 Predicted values for the electron edm de (e.cm) 10-30 - Experimental upper bound T T CP implies 10-32 + 10-34 10-36 Insufficient CP Standard Model

  6. Measuring the EDM – spin precession Gyroscope precessing in a gravitational field Electron precessing in a magnetic field Electron precessing in parallel magnetic and electric fields Electron precessing in anti-parallel magnetic and electric fields Measure change in precession rate when electric field direction is reversed – this is proportional to the EDM To measure the electron EDM, use an electron inside an atom or molecule

  7. Using atoms & molecules to measure e-edm Enhancement factor Interaction energy =-de.Eeff=-de .(hE) E N.B. Analogous to interaction of magnetic dipole moment with a magnetic field, -m .B Eeff = FP Polarization factor Electric Field Atom / Molecule Structure dependent, ~ 10 (Z/80)3 GV/cm For more details, see E. A. Hinds, Physica Scripta T70, 34 (1997)

  8. 1st huge problem: motional interaction m  v  E analyse polarise The solution: add 2 more Tl beams going down E ± dhE hf = mB B 2nd huge problem: ± stray static magnetic fields analyse polarise The solution: Add 4 Na beams for magnetometry 2 Tl atomic beams 4 The Tl edm experiment B.C. Regan, E.D. Commins, C.J. Schmidt and D. DeMille, PRL 88, 071805 (2002) Tl – enhancement factor h = 585 Final result (2002) |de| < 1.6 x 10-27 e.cm (90% CL)

  9. Molecules are even more sensitive than atoms Enhancement factor for YbF Eeff = FP Polarization factor Structure dependent, ~ 10 (Z/80)3 GV/cm For atoms, P ~ 10-3 For molecules, P ~ 1 • “Huge” edm interaction energy (10aeV, 2mHz, 80f cm-1, 100 fK) • Less demanding magnetic field control (dfalse= 3x10-27 e.cm/pT) • Insensitive to B perpendicular to E (suppressed by 1010) • Thus, insensitive to motional-B (Bmot = v E / c2 = 104 pT) For more details, see PRL 89, 023003 (2003)

  10. Result of the YbF EDM experiment • de = (-2.4 ± 5.7stat ± 1.5syst) × 10-28e.cm • | de | < 10.5 × 10-28 e.cm (90% confidence level) For details, see Nature 473, 493 (2011)

  11. 10-22 10-24 MSSM f ~ 1 10-26 Multi Higgs Left -Right MSSM f ~ a/p 10-28 Predicted values for the electron edm de (e.cm) 10-30 10-32 10-34 10-36 Standard Model Measurement & theory Excluded region Our result: | de | < 10.5 × 10-28 e.cm (5 × 10-19 Debye)

  12. CPT – precision spectroscopy of antihydrogen CPT theorem All local, Lorentz-invariant quantum field theories are invariant under CPT Should be tested Magnetic moments (g-2) of e- and e+ Precision spectroscopy of H and anti-H Completed PRL 59, 26 (1987) Being developed Equal – 1 part in 1012 Claimed potential – 1 part in 1018 !! N.B g/2(e-) = 1.00115965218085(76) PRL 97, 030801 (2006) For Hydrogen, f(1s-2s) already measured to 1 part in 1014

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