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Search for hidden sector photons in a microwave cavity experiment. John Hartnett, Mike Tobar , Rhys Povey, Joerg Jaeckel. DURHAM UNIVERSITY. The 5th Patras Workshop on Axions, WIMPs and WISPs. Frequency Standards and Metrology - PowerPoint PPT Presentation
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SEARCH FOR HIDDEN SECTOR PHOTONS IN A MICROWAVE
CAVITY EXPERIMENTJohn Hartnett, Mike Tobar, Rhys
Povey, Joerg Jaeckel
The 5th Patras Workshop on Axions, WIMPs and WISPs
DURHAM UNIVERSITY
Michael E. Tobar ARC Australian Laureate Fellow
School of PhysicsUniversity of Western Australia, Perth
Frequency Standards and Metrology Research Group
Frequency Standards and MetrologyPrecision Microwave Oscillators and Interferometers: From Testing
Fundamental Physics to Commercial and Space Applications
High-Precision Oscillators, Clocks and Interferometers
Generating and measuring frequency, time and phase at the highest precision
Space
ResearchTesting fundamental physics
1. Lorentz Invariance2. Rotating cryogenic oscillator experiment3. Odd parity magnetic MZ Interferometer experiment4. Generation and detection of the Paraphoton
Commercial Applications5. Microwave Interferometer as a noise detector6. Sapphire Oscillators (room temperature and cryogenic)
Atomic Clock Ensemble in Space (ACES) Mission7. Australian User Group 8. Long term operation of high precision clocks
Astronomy9. Cryogenic Sapphire Oscillators better than H-masers10. With MIT, image black hole at the centre of the Galaxy11. Within Australia -> SKA and VLBI timing
Schematic of cavity experiment
Microwave cavity modes Whispering Gallery modes WGE(H)mnp
Vertically stacked
TM0np (n = 0,1; p = 0,1,2,3) Vertically stacked
TE0np (n = 0,1; p = 0,1,2,3) Vertically stacked
Whispering Gallery modes
Electric field strength
WGE16,0,0
HEMEX Whispering Gallery Mode Sapphire resonator
WGH16,0,0 at 11.200 GHz
Cavity mounted inside inner can
Sapphire in Cavity
1911.83
copper nut
51.00
80
30 50sapphire
copper clamp
silver plated copper cavity
primarycoupling probe
secondary coupling probe
10
8
Lower order modesTE mode: Eθ field
Electric field strength
TM010TE011
Coupling to paraphoton
Form Factor |G|
Paraphoton wavenumber
Cavity resonance frequency
Transistion Probability
Resonance Q-factorcoupling
Paraphoton mass
|G|~ 1
Assuming Pem = 1 W, Pdet = 10-24 W, Q ~ 109, χ ~ 3.2 × 10-11
Probability of Detection
Exclusion plotFor 6 pairs of Niobium cylinders (stacked axially) with 2 GHz < ω0/2π < 20 GHz and ω0 k 0
Microwave cavities
Q~1011, ….6 orders of magnitude better than Coulomb experiment
Overlap integral |G|
kγ = paraphotonk0 =ω0/c (resonance) kγ2 =ω2 – mγ
2
Overlap integral |G|
Overlap integral |G|
Overlap integral |G|
Q-factor TE0np
Q =Rs/G G=Geometric factor & Rs = surface resistance
G [O
hms]
Freq [Hz]
10 GHz mode T ≤ 4 K Niobium Q~ 109
SUMO cavity: TM010 mode
WG modes In sapphire very high Q ~ 109 without
Niobium ? G for high m seems small, need to
confirm, as numeric integral needs to be checked
Detection? Assuming
detection bandwidth f = 1 Hz receiver temperature T = 1 K (very good
amp)thermal noise power kTf = -199 dBmPower@ 1paraphoton per second S/N = 1
freq hf/s dBm Seconds10 GHz 6.63E-24 -202 21 GHz 6.63E-25 -212 21
Challenges Isolation will be the biggest problem Microwave leakage Unity coupling probes to cavities No reflected power Tuning High Q resonances exactly to the
same frequency