High Precision , Low Energy Tests of the Standard Model and Its Symmetries

1. High Precision, Low Energy Testsof the Standard Model and Its Symmetries Gerald Gabrielse, Leverett Professor of Physics, Harvard University Spokesperson of the CERN ATRAP Collaboration • Testing the Most Precise Prediction of the Standard Model • Electron magnetic moment • Testing Standard Model Extensions (e.g. Supersymmetry) •  Electron electric dipole moment • Testing the Symmetries of the Standard Model •  Q/M for the antiproton and proton • Antiproton and proton magnetic moments • Positron and electron magnetic moments (underway) • Antihydrogen and hydrogen structure (still in the future) • Comparing Antimatter and Mater Gravity •  Gravitational Redshift of the Antiproton and Proton Supported by US NSF and AFOSR. Antiprotons from CERN

2. Low Energy Particle Physics AMO Physics, Particle Physics, Plasma Physics methods and funding can’t avoid goals and facility LEAR and AD 1010 TRAP 4.2 K 0.3 meV 70 mK, lowest storage energy for any charged particles

4. Electron Magnetic Dipole Moment • Most precisely measured property of an elementary particle • Most precise prediction of the standard model • Most precise confrontation of theory and experiment • Greatest triumph of the standard model

5. The Amazing Electron Electron orbits give atoms their size, but the electron itself may actually have “no size” mass of “ingredients” is 20 million times more than the mass 0.5 MeV/c2 Electron has angular momentum (spin) even though it has no size and nothing is rotating: Magnetic dipole moment: What about electric dipole?

6. Standard Model Prediction 1 Dirac QED essentially exact Hadronic smaller Weak

7. Probing 10th Order and HadronicTerms Dirac QED

8. David Hanneke G.G. Shannon Fogwell

9. Need Good Students and Some Time Elise Novitski Joshua Dorr Shannon FogwellHogerheide David Hanneke Brian Odom, Brian D’Urso, Steve Peil, DafnaEnzer, Kamal Abdullah Ching-hua Tseng Joseph Tan 20 years 8 theses N$F

10. Cylindrical Penning Trap • Electrostatic quadrupole potential  good near trap center • Control the radiation field  inhibit spontaneous emission by 200x (Invented for this purpose:G.G. and F. C. MacKintosh; Int. J. Mass Spec. Ion Proc. 57, 1 (1984)

11. n = 4 n = 3 n = 2 0.1 mm n = 1 n = 0 2 y Need low temperature cyclotron motion T << 7.2 K 0.1 mm Trap with charges - - - - - - - One Electron Quantum Cyclotron - - - - - - -

12. Bohr magneton Quantum Measurement of the Electron Magnetic Moment Spin flip energy: Cyclotron energy: (the magnetometer) Need to resolve the quantum states of the cyclotron motion  Relativistic shift is 1 part in 109 per quantum level

13. Quantum Jump Spectroscopy • one electron in a Penning trap • lowest cyclotron and spin states “In the dark” excitation  turn off all detection and cooling drives during excitation QND – quantum non-demolition detection

14. t= 16 s Inhibited Spontaneous Emission Application of Cavity QED excite, measure time in excited state many other new methods

15. Most precisely measured property of an elementary particle Electron Magnetic Moment Determined to 3 x 10-13 (improved measurement is underway)

16. from measured fine structure constant

17. From Freeman Dyson – One Inventor of QED Dear Jerry, ... I love your way of doing experiments, and I am happy to congratulate you for this latest triumph.  Thank you for sending the two papers. Your statement, that QED is tested far more stringently than its inventors could ever have envisioned, is correct.  As one of the inventors, I remember that we thought of QED in 1949 as a temporary and jerry-built structure, with mathematical inconsistencies and renormalized infinities swept under the rug.  We did not expect it to last more than ten years before some more solidly built theory would replace it.  We expected and hoped that some new experiments would reveal discrepancies that would point the way to a better theory. And now, 57 years have gone by and that ramshackle structure still stands. The theorists … have kept pace with your experiments, pushing their calculations to higher accuracy than we ever imagined. And you still did not find the discrepancy that we hoped for.  To me it remains perpetually amazing that Nature dances to the tune that we scribbled so carelessly 57 years ago.  And it is amazing that you can measure her dance to one part per trillion and find her still following our beat. With congratulations and good wishes for more such beautiful experiments, yours ever, Freeman.

18. Test for Physics Beyond the Standard Model Does the electron have internal structure? limited by the uncertainty in independent a value if our uncertainty was the only limit Not bad for an experiment done at 100 mK, but LEP does better LEP contact interaction limit > 20,000,000 electron masses of binding energy

20. Electron Electric Dipole Moment (EDM) • Most precise test of extensions to the standard model • 12 times more precise than previous measurements Magnetic moment: Electric dipole moment: Does this also exist? Well measured

21. Particle EDM Requires Both P and T Violation Magnetic moment: Electric dipole Moment: If reality is invariant under parity transformations P  d = 0 P T If reality is invariant under time reversal transformations T  d = 0

22. Standard Model of Particle Physics Predicts a Non-zero Electron EDM four-loop level in perturbation theory Standard model: d ~ 10-38 e-cm Too small to measure by orders of magnitude best measurement: d ~ 2 x 10-27 e-cm Weak interaction couples quark pairs (generations) CKM matrix relates to d, s, b quarks (Cabibbo-Kabayashi-Maskawa matrix) almost the unit matrix

23. Extensions to the Standard Model  Much Bigger, Measureable Electron EDM An example Low order contribution  larger moment Low order contribution  vanishes From Fortson, Sandars and Barr, Physics Today, 33 (June 2003)

24. Gerald Gabrielse Leverett Professor Physics, Harvard University Improved Electron Electric Dipole Momentand What is Next Advanced Cold Molecule EDM Science 343, 269 (2014) NSF, and NIST

25. ACME Collaboration Joint effort of 3 research groups Gerald Gabrielse (Harvard) David DeMille (Yale) John Doyle (Harvard) ACME PhD Ben Spaun Chris Panda Nick Hutzler Adam West Brendon O’Leary Paul Hess Jacob Baron Elizabeth Petrik Earlier: Amar Vutha, YuliaGurevich, Emil Kirilov, Ivan Kozyreyv, Wes Campbell

26. Before Our ACME Measurement of Electron EDM Before ACME ACME aspiration for first 5 years W. Bernreuther, M. Suzuki, Rev. Mod. Phys. 63, 313 (1991)

27. How to Measure an Electron EDM Put the EDM in an Electric Field bigger is better Measure the energy shift for the system

28. Cannot Use Electric Field Directlyon an Electron or Proton Simple E and B can be used for neutron EDM measurement (neutron has magnetic moment but no net charge) Electric field would accelerate an electron out of the apparatus Electron EDM are done within atoms and molecules (first molecular ion measurement is now being attempted)

29. Schiff Theorem – for Electron in an Atom or Molecule • Schiff (1963) – no atomic or molecular EDM (i.e. linear Stark effect) • from electron edm • nonrelativistic quantum mechanics limit • Sandars (1965) – can get atomic or molecular EDM (i.e. linear Stark effect) • from electron edm • relativistic quantum mechanics • get significant enhancement (D >> d) for large Z • Commins, Jackson, DeMille (2007) – intuitive explanation Schiff •  Lorentz contraction of the electron EDM in lab frame Schiff, Phys. Rev. Lett. 132, 2194 (1963); Sandars, Phys. Rev. Lett. 14, 194 (1965); ibid22, 290 (1966). Commins, Jackson, DeMille, Am. J. Phys. 75, 532 (2007).

30. Why Use a Molecule? To Make Largest Possible Electric Field on Electron Tl atom (best EDM limit till YbF) ThO molecule Molecule can be more easily polarized using nearby energy levels with opposite parity (not generally available in atoms)

31. Still, the EDM Gives Tiny Shift of Energy Levels 2 mHz Not so easy to resolve To detect  let a prepared wave function evolve for time T large as possible Example is for an electron edm equal the ACME upper limit.

32. Detect aSmall Phase Shift set by choice of direction of the first of the two orthogonal detection laser polarizations set by choice of dark state time in E, B y y x x Example is for an electron edm equal the ACME upper limit.

33. Experiment in Two Labs – 100 Meters Separated Harvard Jefferson Building Harvard LISE Building ThO Source and Interaction Chamber (2 floors down) 100 m optical fibers Lasers, Iodine Clock, Comb

34. ThO Molecular Beam Pulse Tube Cooler Molecular Beam Source “Interaction Region”: E-field plates inside, B-field shields and coils outside Pulsed YAG Molecule Trajectory PrepLasers Probe Lasers Lasers 100m away 34

35. Magnetic Field Coils and Shielding mu metal endplates 5 shields (no shown) ~ 10-5 shielding ThO beam Interaction chamber inside Cos(theta) coils to provide transverse B field 200 mG with uniformity of 10-3 over 26 cm

36. Detect the Tiny Phase Shift  Interference set by choice of direction of the first of the two orthogonal detection laser polarizations set by choice of dark state  maximize sensitivity to

37. Detecting an EDM superposition evolve: E + edm combine emit ground state B E cold ThO source light detector electric field plates magnetic field apparatus control and data acquisition

38. Total Phase Equation: single block 10 blocks averaged 3 ± 5 x 10-5rad phase (rad) block (~1 min) 392 ± 5 x 10-5rad phase (rad) block (~1 min) ??? ± 5 x 10-5rad phase (rad) block (~1 min)

39. -3590 ± 5 x 10-5rad phase (rad) single block 10 blocks averaged -1530 ± 5 x 10-5rad phase (rad) -2 ± 5 x 10-5rad phase (rad) block (~1 min) block (~1 min) 4 ± 5 x 10-5rad phase (rad) block (~1 min) -1 ± 5 x 10-5rad phase (rad) block (~1 min)

41. Constraining New Physics on the 1 to 3 TeV Scale difficult to suppress new CP violating phase for weak interactions ~4/137 mass scale of new particles prefactor couples to weak interaction via n=1 or n=2 loop diagrams 3 TeV 1 TeV conservative Probing same mass scale as the LHC

42. We need molecular theory to get the effective electric field We actually constrain the EDM and CS Assuming d=0

43. New ACME Electron EDM Measurement New ACME Result Do NOT quote our hopes till we realize them!!!

44. How Big is 8 x 10-29 e cm? How sensitive was our princess to the hidden pea? Scale size of the polarization cloud around the electron  earth Shift in earth center by 2 nm earth-sized polarization cloud around electron (scale classical electron radius)

45. Relationship to LHC Physics • The LHC is exciting and important but EDMs also play a role • should get an improved electron EDM on the LHC time scale • If the LHC sees new particles, is CP violation involved? • If the LHC sees nothing, EDM game is the only one in town • Would be great to use LHC results and ours together to see what • we have learned together about Standard Model extensions

46. https://twiki.cern.ch/twiki/pub/AtlasPublic/CombinedSummaryPlots/AtlasSearchesSUSY_SUSY2013.pdfhttps://twiki.cern.ch/twiki/pub/AtlasPublic/CombinedSummaryPlots/AtlasSearchesSUSY_SUSY2013.pdf

48. Testing the Standard Model’s Fundamental SymmetryandComparing Antimatter-Matter Gravity

49. Single Particle MeasurementsHave Three Big Advantages Can be done with antiparticles Can reach a much higher precision Direct measurement  same measurement and apparatus is used with a particle and antiparticle

50. Most Stringent Tests of the Standard Model (and Gravity) with Antiprotons Q/M of Antiproton and Proton – most stringent test of the Standard Model’s CPT theorem with baryons Comparison of Antiproton and Proton Gravity 680 Times Improved Comparision of the Antiproton and Proton Magnetic Moments