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No s is Good News

No s is Good News. (The Quest for Neutrinoless Double b Decay). S. Biller, Oxford University. The Paradigm:. For each flavour, “fundamental” symmetric state has 4 distinct n s:. n R (=n R ). n L n R n L n R. Mixed “Majorana” states have coupled masses: “See-Saw”.

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No s is Good News

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  1. No s is Good News (The Quest for Neutrinoless Double b Decay) S. Biller, Oxford University

  2. The Paradigm: For each flavour, “fundamental” symmetric state has 4 distinct ns: nR (=nR) nL nR nL nR Mixed “Majorana” states have coupled masses: “See-Saw” nL(= nL) If lepton number is not a conserved quantity, mixing between n & n can occur (like kaons)

  3. The Paradigm: For each flavour, “fundamental” symmetric state has 4 distinct ns: nR (=nR) CP violation nL nR nL nR ~ GUT scale Mixed “Majorana” states have coupled masses: “See-Saw” Predominantly decay to matter Cross-over to baryons (“Sphalerons”) nL(= nL) Leptogenesis If lepton number is not a conserved quantity, mixing between n & n can occur (like kaons) ~ sub-ev scale

  4. Majorana Reasons To Try Marijuana: • Would provide an extremely sensitive • probe of the absolute neutrino mass • Seesaw mechanism with GUT-scale • Majorana neutrino could explain scale • of observed neutrino masses • Coupled with CP violation, would be • a key feature of Leptogenesis

  5. First Attempt: Produce neutrinos at the lowest possible energy, then physically boost to frame of reversed helicity ne e- Lowest known Q value for beta decay: 115In 115Sn(3/2+) Q = 155 eV !! g ~ 100 eV 0.1 eV = 103 Br = 10-4 E(115In) ~ 100 TeV Easier ways to earn a living !!! s~ 10-47 cm2/eV

  6. TheONLYPotentially Viable Approach Known is Neutrinoless Double b Decay

  7. Single Beta Decay u d d u d u W e- ne

  8. Double Beta Decay u d d u d u W e- Maria Goeppert-Mayer 1935 ne ne e- Elliott, Hahn & Moe 1988 (82Se) W d d u u d u

  9. Double Beta Decay u d d u d u W e- Ettore Majorana 1937 Maria Goeppert-Mayer 1935 ne ne However, if ne could somehow change into ne … e- Elliott, Hahn & Moe 1988 (82Se) W d d u u d u Wendell Furry 1939

  10. Double Beta Decay u d d u d u W e- Ettore Majorana 1937 Maria Goeppert-Mayer 1935 ne ne However, if ne could somehow change into ne … e- Elliott, Hahn & Moe 1988 (82Se) W d d u u d u Wendell Furry 1939

  11. Neutrinoless Double Beta Decay u d d u d u W e- e- Ettore Majorana 1937 Maria Goeppert-Mayer 1935 ne ne However, if ne could somehow change into ne … ne e- e- Elliott, Hahn & Moe 1988 (82Se) W d d u u d u Wendell Furry 1939

  12. G0n = G0n(E0,Z) |M0nGT – (gV/gA)2 M0nF|2 <mn>2 Exactly calculable phase integral Nuclear matrix elements (not so exactly calculable) Effective neutrino mass = SmiU2ei

  13. So, ½ 1/sdetection G bound G bound <mn> bound ∞ ∞ ∞ ∞ ∞ ∞ Signal Dominated Regime Background Dominated Regime s s MT √MTDE S √B ≈ (S)½ ≈ (MT)½ target counting mass time energy range examined Ouch! 1/4 DE MT 1/4 1 MT <mn> bound <mn> bound

  14. H.V. KLAPDOR-KLEINGROTHAUS et al., 2001 76Ge

  15. NEMO 3

  16. Internal Backgrounds: External Backgrounds:

  17. SuperNEMO UK Involvment: UCL, Manchester, Imperial

  18. Laboratoire Souterrain de Modane

  19. UK cost ~10-15M

  20. SNO+ Physics with Liquid Scintillator • Neutrinoless double beta decay • pep and CNO low energy solar neutrinos • tests details of neutrino-matter interaction • solve “Solar Composition Problem” • Low energy 8B solar neutrinos (& possibly 7Be) • Geo-neutrinos • 240 km baseline reactor neutrino oscillations • Supernova neutrinos Leeds, Liverpool, Oxford, QMUL, Sussex Replace 1000 tonnes of ultrapure D2O with 800 tonnes of ultrapure scintillator (so, technically, should be “SNO-”)

  21. Now part of larger SNOLAB major underground science facility. Nigel Smith is the new director.

  22. SNO+ AV Hold Down Existing AV Support Ropes

  23. SNO+ AV Hold Down Existing AV Support Ropes AV Hold Down Ropes

  24. Electronics refurbishment • Improved cover-gas system • New glovebox • Repair of liner • Re-sanding of acrylic vessel • Overhaul of software design • New calibration systems • New purification systems • Replacement of pipes

  25. 150Nd (5% natural abundance) Loaded by carboxylate technique developed at Brookhaven Radio-purification goals: < 10-17 g 228Ra/228Th per g scintillator demonstated by Borexino & KamLAND 228Th and 228Ra in 10 tonnes of 10% Nd (in form of NdCl3 salt) down to < 10-14 g 232Th/g Nd A reduction of >106 relative to raw salt measurement!!!

  26. mixing

  27. Purification Spike Tests • spike scintillator with 228Th (80 Bq) which decays to 212Pb • counted by β- coincidence liquid scintillation counting

  28. 3 Years of data, mn=350meV, U/Th = 10-17 g/g 0.1% natural Nd loading, IBM-2 matrix elements 1st data 2012 Clear confirmation or restrictive bound below Klapdor region by 2015

  29. How do you firmly establish whether a possible signal is actually 0n2b ? 1) Redundancy Two methods: 2) Redundancy Different isotopes with signals predicted at different energies, with different backgrounds, and different signal rates that scale correctly with the corresponding matrix elements.

  30. 600 500 400 300 200 100 0 Klapdor-Kleingrothaus SUPER NEMO mn (meV) GERDA I COBRA ? SNO+ EXO KAMLAND SNO+ SUPER NEMO GERDA II CUORE CUORE SNO+ II ? Inverted Heirarchy CUORE II ? 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

  31. OUTLOOK: By 2015, neutrino masses above ~100 meV will either be firmly established or firmly ruled out based on multiple experiments (including SNO+) using different isotopes. If established, first constraints on several physics mechanisms will likely be made using ratios of lifetimes in these different isotopes. By 2020, SuperNEMO will be also able to confirm signal with Se and use independent method to further constrain RH-current models. If ruled out, all experiments will have to push to larger masses/enrichment to properly test inverted hierarchy. First experiments here might be running by ~2018.

  32. SNO+ Status: oFully funded by Canada and will start taking data in 2012 oUnique detector and facility are firmly established o Remarkably Diverserange of unique physics capabilities oExtremely timely: “could be ready earlier than other competitors.” (PPAN) oExtremely cost-effective: For UK, basically just fEC, travel and postdocs (no major hardware, no operating costs, no Common Fund, etc.) “Capitalising on existing infrastructure” (PPAN) (not to mention many years of PPARC/STFC investment) UK cost ~3M oExtremely High UK Impact: Capitalising on more than 20 years of intellectual investment with track record of significant high profile contributions leading to groundbreaking result and with 10 permanent academics (1/3 of those on entire project) o“There is a strong case for the UK to make the require modest investment to participate in SNO+” (PPAP) oRatedAlpha-4 (PPAN)

  33. 600 500 400 300 200 100 0 Klapdor-Kleingrothaus SUPER NEMO mn (meV) GERDA I COBRA ? SNO+ EXO KAMLAND SNO+ SUPER NEMO GERDA II CUORE CUORE SNO+ II ? Inverted Heirarchy CUORE II ? 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

  34. SNO+ Double Beta Decay • A liquid scintillator detector has poor energy resolution... but HUGE quantities of isotope (high statistics) and low backgrounds help compensate • Large, homogeneous liquid detector leads to well-defined background model • fewer types of material near fiducial volume (meters of self-shielding) • “Source in”/“Source out” capability to test backgrounds, improve purification, etc. • Interesting new technique with a rapid timescale

  35. Which Mechanism? RH Currents SUSY Models Extra Dimensions

  36. Deppisch & Päs, 2007 also Gehman & Elliott, 2007

  37. q

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