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

13. = E = mc 2

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

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

26. Detecting at SNO NC xx    npd ES --    e e xx CC - epd  e p Low Statistics  ( e )  6  (  )  6  (  ) Strong directionality: Measurement of e energy spectrum Weak directionality: Measure total 8 B flux from the sun  e     

27. See : Phys.Rev.Lett. 89 (2002) 011301 Phys.Rev.Lett. 89 (2002) 011302 Solar Model predictions are verified: [in 10 6 cm -2 s -1 ] Missing Solar ’s Found 8 B  shape constrained fit: No 8 B  shape constraint: Null hypothesis of no flavour transformation rejected at 5.3 

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

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

32. Is Oscillation Really the Solution? Kamioka Liquid scintillator Anti-Neutrino Detector (KamLAND) (Kamioka, Gifu Prefecture, Japan)  reactor  @ “right” baseline for directly testing the currently favoured LMA region 2x coincidence 1 kt liquid scintillator as target (inverse  decay)

33. Reactor Anti-Neutrino Flux N obs /N no oscillation N observed – N BKG N no oscillation = 0.611 ± 0.085 (stat) ± 0.041 (syst) First observation of reactor anti-neutrino deficit LMA prediction:  m 2 = 5.5x10 -5 eV 2 sin 2 2  = 0.833

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

52. 56 events seen---80 expected

61. 0 4 2 8 10 6 -2 t b  c s  d u e Log 10 m/eV (  m 2 atm ) 1/2 (  m 2 sol ) 1/2 Upper limit on m Neutrino masses are really special! m t /(  m 2 atm ) 1/2 ~10 12 WMAP & LSS KamLAND Massless ’s? no R L conserved Small  masses? R very heavy L not conserved

64.  /  dm  dm

71. 6p  4 He + 2p +2e + + 2 Twice 

72. 4p + e -  4 He + e + +2

73. Solar neutrino mixing