Search for hidden sector photons in a microwave cavity experiment

1. 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

2. Frequency Standards and Metrology Precision Microwave Oscillators and Interferometers: From Testing Fundamental Physics to Commercial and Space Applications FSM Michael E. Tobar ARC Australian Laureate Fellow School of Physics University of Western Australia, Perth Frequency Standards and Metrology Research Group

3. High-Precision Oscillators, Clocks and Interferometers Generating and measuring frequency, time and phase at the highest precision Space

4. Research Testing fundamental physics • Lorentz Invariance • Rotating cryogenic oscillator experiment • Odd parity magnetic MZ Interferometer experiment • Generation and detection of the Paraphoton Commercial Applications • Microwave Interferometer as a noise detector • Sapphire Oscillators (room temperature and cryogenic) Atomic Clock Ensemble in Space (ACES) Mission • Australian User Group • Long term operation of high precision clocks Astronomy • Cryogenic Sapphire Oscillators better than H-masers • With MIT, image black hole at the centre of the Galaxy • Within Australia -> SKA and VLBI timing

6. Schematic of cavity experiment

7. 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

8. Whispering Gallery modes

9. Electric field strength WGE16,0,0

10. HEMEX Whispering Gallery Mode Sapphire resonator WGH16,0,0 at 11.200 GHz

11. Cavity mounted inside inner can

13. Sapphire in Cavity 80 8 sapphire 30 50 secondary coupling probe 51.00 11.83 19 silver plated copper cavity copper clamp 10 primary coupling probe copper nut

16. Lower order modes TE mode: Eθ field

17. Electric field strength TE011 TM010

19. Coupling to paraphoton

20. Form Factor |G| Paraphoton wavenumber Cavity resonance frequency

21. Transistion Probability coupling |G|~ 1 Paraphoton mass Resonance Q-factor

22. Probability of Detection Assuming Pem = 1 W, Pdet = 10-24 W, Q ~ 109, χ ~ 3.2 × 10-11

23. Exclusion plot For 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

24. Overlap integral |G| k0 =ω0/c (resonance) kγ = paraphoton kγ2 =ω2 – mγ2

25. Overlap integral |G|

26. Overlap integral |G|

27. Overlap integral |G|

31. Q-factor TE0np • Q =Rs/G G=Geometric factor & Rs = surface resistance G [Ohms] 10 GHz mode T ≤ 4 K Niobium Q~ 109 Freq [Hz]

32. SUMO cavity: TM010 mode

33. 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

34. Detection? • Assuming • detection bandwidth f = 1 Hz • receiver temperature T = 1 K (very good amp) thermal noise power kTf = -199 dBm

35. 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