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Neutrinos

Neutrinos. Arguably the most fascinating of the elementary particles. Certainly they take us beyond the Standard Model !. Louvain, February 2005 Alan Martin. =. E = mc 2. Solar Neutrino Problem (circa 2000). either Solar models are incomplete/incorrect or

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Neutrinos

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  1. Neutrinos Arguably the most fascinating of the elementary particles. Certainly they take us beyond the Standard Model ! Louvain, February 2005 Alan Martin

  2. = E = mc2

  3. Solar Neutrino Problem (circa 2000) either Solar models are incomplete/incorrect or Neutrinos undergo flavor-changing transformation

  4. 2 km to surface Sudbury Neutrino Observatory 1006 tonnes D2O 17.8m dia. PMT Support Structure 9456 20-cm dia. PMTs 56% coverage 12.01m dia. acrylic vessel 1700 tonnes of inner shielding H2O Urylon liner 5300 tonnes of outer shielding H2O Nucl. Inst. Meth. A449, 127 (2000)

  5. p n +  + + - CC d p e e n +  + + n NC d p n x x ES - - +  + n e n e x x Detecting  at SNO • Measurement ofneenergy spectrum • Weak directionality: • Measure total 8Bnflux from the sun • s(ne) = s(nm) = s(nt) • Low Statistics • s(ne)  6 s(nm)  6 s(nt) • Strong directionality:

  6. Missing Solar n’s Found Null hypothesis of no flavour transformation rejected at 5.3s See : Phys.Rev.Lett. 89 (2002) 011301 Phys.Rev.Lett. 89 (2002) 011302 Solar Model predictions are verified: [in 106 cm-2 s-1] 8Bn shape constrained fit: No 8Bn shape constraint:

  7. If CPT is conserved…(and LMA…) Predicts deficit in Solar ne Reactor ne ~100 to 200 km Complementary!

  8. Why Kamioka? 51 reactors in Japan, 80% of flux (or 68.5 GW of reactor power) from baseline of ~140 to 210 km

  9. Is n Oscillation Really the Solution? • KamiokaLiquidscintillatorAnti-NeutrinoDetector(KamLAND) (Kamioka, Gifu Prefecture, Japan) • reactor n @ “right” baseline for directly testing the currently favoured LMA region 1 kt liquid scintillator as target 2x coincidence (inverse b decay)

  10. LMA prediction: m2 = 5.5x10-5 eV2 sin2 2 = 0.833 Nobs/Nno oscillation Nobserved – NBKG Nno oscillation = 0.611 ± 0.085 (stat) ± 0.041 (syst) Reactor Anti-Neutrino Flux First observation of reactor anti-neutrino deficit

  11. Atmospheric neutrinos Electron neutrinos as expected. Evidence of mu-tau neutrino oscillations. Should see evidence of upgoing tau neutrinos

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