1 / 59

Hamish Robertson, CENPA, University of Washington

Direct probes of neutrino mass Neutrino Oscillation Workshop NOW2014, Otranto Italy Sept. 8. Hamish Robertson, CENPA, University of Washington. What is the neutrino mass scale?. Particle Physics Cosmology.

morrie
Download Presentation

Hamish Robertson, CENPA, University of Washington

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Direct probes of neutrino mass Neutrino Oscillation Workshop NOW2014, Otranto Italy Sept. 8 Hamish Robertson, CENPA, University of Washington

  2. What is the neutrino mass scale? Particle Physics Cosmology Some things are simply missing from the standard model (dark matter, gravity…) but neutrino mass is the only contradiction to the SM.

  3. Neutrino mass from Beta Spectra With flavor mixing: mixing neutrino masses from oscillations mass scale

  4. Present Laboratory Limit from 2 tritium experiments: Together:… mv < 1.8 eV (95% CL)

  5. Mass and mixing parameters Oscillation Kinematic Marginalized 1-D 1- uncertainties. *C. Kraus et al., Eur. Phys. J. C40, 447 (2005); V. Aseev et al. PRD 84 (2011) 112003. Other refs, see Fogli et al. 1205.5254

  6. AtKarlsruhe Institute of Technology uniquefacilityforclosed T2cycle: Tritium Laboratory Karlsruhe KATRIN A direct, model-independent, kinematic method, based on β decay of tritium. TLK ~ 75 m longwith 40 s.c. solenoids

  7. ES

  8. A window to work in Molecular excitations Energy loss

  9. KATRIN’s uncertainty budget σ(mv2) 0 0.01 eV2 Statistical Final-state spectrum T- ions in T2 gas Unfolding energy loss Column density Background slope HV variation Potential variation in source B-field variation in source Elastic scattering in T2 gas σ(mv2)total= 0.025 eV2 mv< 0.2 eV(90 % CL)

  10. Overview of KArlsruheTRItiumNeutrino Experiment Windowless gaseous source Transport section Pre-spectrometer Main-spectrometer Detector 10-3 mbar 10-11 mbar V Monitor-spectrometer 70 m

  11. K. Valerius

  12. Neutrino mass signal

  13. Sensitivity with Time

  14. starting 2016 KATRIN Present Lab Limit 1.8 eV Mass Range Accessible

  15. The Last Order of Magnitude If the mass is below 0.2 eV, how can we measure it? KATRIN may be the largest such experiment possible. σ(mv)2 ~ 0.38 eV2 Size of experiment now: Diameter 10 m. Source T2 column density near max Rovibrational states of THe+, HHe+ molecule Next diameter: 300 m!

  16. A new idea.

  17. Cyclotron radiation from tritium beta decay (B. Monreal and J. Formaggio, PRD 80:051301, 2009) Surprisingly, this has never been observed for a single electron.

  18. The energy is measured as a frequency Tritium endpoint

  19. Energy rEsolution

  20. Power Radiated

  21. G-M cooler (35K) 26-GHz amplifiers 83mKr source (behind) SC Magnet (0.95 T) Prototype at University of Washington

  22. Gas cell is a small section of WR-42 waveguide

  23. 52 mm

  24. Superheterodyne receiver

  25. What would a signal from an electron look like? Digitize the amplifier output. Make short-time Fourier transforms. Plot the spectra sequentially (a “spectrogram”). Simulation: M. Leber

  26. Energy spectrum 83mKr

  27. “jump” spectrum 83mKr 30.4 keV line Most probable jump is 14 eV.

  28. Next: a tritium experiment Fill a volume with tritium gas at low pressure Instrument with antennas and receivers Apply uniform magnetic field Measure the spectrum

  29. Project 8 sensitivity and OPTIMISTIC

  30. Project 8: a phased approach

  31. starting 2016 KATRIN Present Lab Limit 1.8 eV Mass Range Accessible

  32. Neutrino Mass Limits from Beta decay

  33. summary • Direct mass measurements are largely model independent: • Majorana or Dirac • No nuclear matrix elements • No complex phases • No cosmological degrees of freedom • One experiment in construction (KATRIN); 2016 start. • Three experiments in R&D (Project 8, ECHo, PTOLEMY) • Success of Project 8 proof-of-concept. • New spectroscopy based on frequency • First step toward frequency-based determination of neutrino mass

  34. Fin

  35. Neutrino mass: some milestones Construction Running 2013 2014 2015 2016 2017 2018 2019 KATRIN: Proof concept Prototype Phase I Project 8:

  36. Neutrino mass Physics Impact

  37. Battye and Moss, PRL 112, 051303 (2014) Lensing power spectrum • Planck • SPT Some tensions in ΛCDM resolved with neutrino mass: Shear correlation spectrum • CFHTLenS

  38. Cyclotron radiation from tritium beta decay (B. Monreal and J. Formaggio, PRD 80:051301, 2009) Radiated power ~ 1 fW Early 25.5-GHz waveguide cell Working on the UW prototype

  39. Is an atomic source feasible? • Must reject molecules to 10-5 (endpoint is 8 eV higher) • Produce T in RF discharge: 90:10 T2:T • Cool to 140 K in aluminum or sapphire tube. • Inject into trap, trap low-field seeking polarization. • Trap and cool to ~1 K by scattering from 4He. • Trap in same magnetic field configuration that is trapping the electrons: bathtub axial trap + added barrel conductors. High fields are essential: complicated SC magnet. 5T ~ 3.1 K. • Neither T2 nor 4He are trapped magnetically. • Surprisingly, all of this looks sort of feasible, not easy. • The statistical accuracy alone doesn’t convey the added confidence an atomic source would give.

More Related