ELECTRON-EDM Van Swinderen Institute for Particle Physics and - - PowerPoint PPT Presentation

ELECTRON-EDM

Steven Hoekstra electron-EDM program leader Van Swinderen Institute for Particle Physics and Gravity University of Groningen LOW-ENERGY PRECISION MEASUREMENTS

Low-energy precision measurements: the electron-EDM program 2

Low-energy precision measurements:

• Key contribution of Van Swinderen Institute for Particle Physics and

Gravity within Nikhef

• University of Groningen joined Nikhef in 2016

Measuring the electron’s electric dipole moment (eEDM):

• NWO funded program 2017-2023
• University of Groningen (RUG), Vrije Universiteit Amsterdam (VU)
• 7 staff, 7 PhD students, 2 postdocs
• Many master (1yr) and bachelor (3mo) students
• Building on existing expertise and infrastructure

THE ELECTRON-EDM PROGRAM

Ba F

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THE TEAM

ANNUAL MEETING SEPT 2018 Ba F

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Low-energy precision measurements: the electron-EDM program

Electron-EDM

• EDM arises from T-violating interactions with heavy

particles in SM extensions

• A clean probe for new physics
• EDM heavily suppressed in the Standard Model
• Current EDM sensitivity probes up to 30 TeV
• Multihiggs, supersymmetry, leptoquarks, …

THE ELECTRIC DIPOLE MOMENT

+ −

EDM SPIN

4 Low-energy precision measurements: the electron-EDM program Ba F

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Exploit the extreme precision of atomic and molecular physics

• We can measure mHz shift (10-18 eV) of energy levels

Chose sensitive system and optimise techniques

• Use the electron in a heavy polar molecule: BaF
• 106 sensitivity enhancement through E-field inside polar molecule
• Exploit long interaction times for increased sensitivity

TABLE-TOP PARTICLE PHYSICS

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B a F

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Principle of measurement: Ramsey interferometer

• Create superposition state, accumulate phase difference, readout
• Sensitivity to small energy shift scales with coherent interaction time
• Therefore, use slow (30 m/s) and cold (100 K) beam of molecules

LONG INTERACTION TIME μ

T

Interference fringes Ramsey π/2 pulses

3 2 1 1 2 3 1 1 1

Increasing T

π/2 pulse π/2 pulse

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Combine state-of-the-art techniques from AMO physics:

• Cryogenic buffergas molecular beam source
• Stark deceleration
• Molecular laser cooling
• Magnetic field shielding

OUR APPROACH

cryogenic source decelerator state preparation interaction

• ptical detection

laser cooling guide ~0.5 m ~4.5 m

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MOLECULE DECELERATOR

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CURRENT STATUS

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CRYOGENIC MOLECULAR BEAM SOURCE OPERATIONAL BaF BEAM AND LASERS OPERATIONAL MOLECULE DECELERATOR OPERATIONAL

12 13 14 15 16 17 18 19 100 200 300 400 500 300 m/s 200 m/s 175 m/s Photon counts Time of flight (ms)

150 M/S SrF MOLECULAR BEAM FLUORESCENCE

Gas bottle (Ar + SF6 ) Ablation Laser (532 nm) Detection Laser (663 nm) Valve Skimmer Stepper Motor Photo Multiplier Tube

F I R S T S I G N A L

Low-energy precision measurements: the electron-EDM program 10

CURRENT STATUS

Ba F

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MAGNETIC SHIELDING DESIGN COMPLETED EFFECTIVE ELECTRIC FIELD CALCULATED BAF MOLECULAR STRUCTURE INVESTIGATED

10 20 30 40 50 1 2 3 4 5 Eeff (GV/cm) Applied electric field (kV/cm) Effective electric field in BaF

Low-energy precision measurements: the electron-EDM program

Low-energy precision measurements

• Searching for new physics through a measurement of the

electron-EDM with cold molecules

• Table-top particle physics with a potential for high impact
• Research program on track, first publications coming out

CONCLUSION

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Low-energy precision measurements: the electron-EDM program 11 Ba F

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