Presentation on theme: "Neutrinos Louvain, February 2005 Alan Martin Arguably the most fascinating of the elementary particles. Certainly they take us beyond the Standard Model."— Presentation transcript:
Neutrinos Louvain, February 2005 Alan Martin Arguably the most fascinating of the elementary particles. Certainly they take us beyond the Standard Model !
Solar Neutrino Problem (circa 2000) either Solar models are incomplete/incorrect or Neutrinos undergo flavor-changing transformation
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
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
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
If CPT is conserved…(and LMA…) Solar e Predicts deficit in Reactor e ~100 to 200 km Complementary!
Why Kamioka? 51 reactors in Japan, 80% of flux (or 68.5 GW of reactor power) from baseline of ~140 to 210 km
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)
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
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
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