1. 8/5/2002Ulrich Heintz - Quarknet 20021 neutrino puzzles Ulrich Heintz Boston University http://physics.bu.edu/quarknet/2002/neutrinos.ppt

2. 8/5/2002Ulrich Heintz - Quarknet 20022 outline the neutrino atmospheric neutrinos solar neutrinos accelerator neutrinos does it make sense?

3. 8/5/2002Ulrich Heintz - Quarknet 20023 the neutrino in the standard model e e ud 0.511 MeV0a few MeV  cs 106 MeV01100 MeV150 MeV  tb 1.8 GeV0175 GeV4.2 GeV leptons quarks spin = ½ (fermions) The Standard Model

4. 8/5/2002Ulrich Heintz - Quarknet 20024 neutrino properties how do we detect neutrinos? –no charge, no color –neutrinos interact only by the weak force –can penetrate entire earth without interacting –need lots of neutrinos and big detectors limits on the neutrino masses –mass of e < 3 eV (  decay of 3 H) –mass of  < 0.19 MeV (  + !  + +  ) –mass of  < 18 MeV (  - !  -  -  +  )

5. 8/5/2002Ulrich Heintz - Quarknet 20025 origin of atmospheric neutrinos cosmic rays interact in upper atmosphere    decay   e decay expect two  per e energy ¼ 1 GeV ++ p ++  e+e+ e 

6. 8/5/2002Ulrich Heintz - Quarknet 20026 neutrino detection neutrino interaction with matter –electron neutrinos ( e ) produce electrons (e) –muon neutrinos (  ) produce muons (  ) –tau neutrinos (  ) produce taus (  ) e e e e W  e e  W

7. 8/5/2002Ulrich Heintz - Quarknet 20027 water Čerenkov detector

8. 8/5/2002Ulrich Heintz - Quarknet 20028 Super Kamiokande 41 m 39 m 3 km2 km 1 km outer detector: 1867 8” tubes 50 ktons H 2 O inner detector: 11146 20” tubes

9. 8/5/2002Ulrich Heintz - Quarknet 20029 Super Kamiokande

10. 8/5/2002Ulrich Heintz - Quarknet 200210 e in SuperK

11. 8/5/2002Ulrich Heintz - Quarknet 200211  in SuperK

12. 8/5/2002Ulrich Heintz - Quarknet 200212 what’s this?

13. 8/5/2002Ulrich Heintz - Quarknet 200213 e and  flux versus zenith angle

14. 8/5/2002Ulrich Heintz - Quarknet 200214 neutrino oscillations  e strength of mixing distance travelled momentum mass difference

15. 8/5/2002Ulrich Heintz - Quarknet 200215 neutrino oscillations p = 400 MeV range of momenta centered on 400 MeV p(  ! e ) distance traveled (m)

16. 8/5/2002Ulrich Heintz - Quarknet 200216 atmospheric neutrinos what does this mean? –  disappear –   e would see e –     is hard to see –  from top no oscillations –  from bottom oscillations –limit parameters

17. 8/5/2002Ulrich Heintz - Quarknet 200217 e and  flux versus zenith angle

18. 8/5/2002Ulrich Heintz - Quarknet 200218 neutrino mixing parameters maximal mixing – sin 2 2  ¼ 1 small  m 2 –  m 2 ¼ 10 -3 eV 2

19. 8/5/2002Ulrich Heintz - Quarknet 200219 K2K to check Super-K results –shoot  beam from KEK to Kamiokande (K2K) –  energy ¼ 1.3 GeV –count  events at Super-K if there are oscillations expect a deficit of  ’s (disappearance) not enough energy to make  ’s (appearance)

20. 8/5/2002Ulrich Heintz - Quarknet 200220 earth how to make a neutrino beam? ++ p ++  e+e+ e  p ++  ++ target

21. 8/5/2002Ulrich Heintz - Quarknet 200221 K2K

22. 8/5/2002Ulrich Heintz - Quarknet 200222 do they oscillate? beam events at Super-K –observe 56 –expect 80 –probability for this without oscillations: ¼ 1%

23. 8/5/2002Ulrich Heintz - Quarknet 200223 Super-K accident on November 12, 2001 –6779 of 11146 inner tubes collapsed –rebuild with 47% of tubes by fall 2002 –complete rebuild after that

24. 8/5/2002Ulrich Heintz - Quarknet 200224 solar neutrinos

25. 8/5/2002Ulrich Heintz - Quarknet 200225 reactions in the sun p+p  2 H+e + + e p+e - +p  2 H+ e 2 H+p  3 He+  3 He+ 3 He  4 He+2p 3 He+p  4 He+e + + e 3 He+ 4 He  7 Be+  7 Be+p  8 Be+  8 Be  8 B * +e + + e 8 B *  4 He+ 4 He 7 Be+e -  7 Li+ e 7 Li+p  4 He+ 4 He

26. 8/5/2002Ulrich Heintz - Quarknet 200226 standard solar model

27. 8/5/2002Ulrich Heintz - Quarknet 200227 solar neutrino experiments SAGE, GALLEX – e + 71 Ga  71 Ge+e  flux = 0.558 SSM Homestake – e + 37 Cl  37 Ar+e -  flux = 0.33 SSM Super-K – x +e -  x +e -  flux = 0.46 SSM

28. 8/5/2002Ulrich Heintz - Quarknet 200228 solar neutrino in Super-K

29. 8/5/2002Ulrich Heintz - Quarknet 200229 the solar neutrino puzzle

30. 8/5/2002Ulrich Heintz - Quarknet 200230 Sudbury Neutrino Observatory Creighton Mine, Sudbury, Ontario 1000 tonnes D 2 O in 12 m diameter acrylic vessel 9500 PMTs in 17 m diameter support 7000 tonnes H 2 O Surrounded by norite rock 2039m to surface. 10 11 m to sun.

31. 8/5/2002Ulrich Heintz - Quarknet 200231 Sudbury Neutrino Observatory

32. 8/5/2002Ulrich Heintz - Quarknet 200232 neutrino reactions in SNO “charged current” “neutral current” “elastic scattering” e e W n p p p x x Z n n p p electron neutrinos only all neutrinos e e e e Z mostly electron neutrinos

33. 8/5/2002Ulrich Heintz - Quarknet 200233 observed neutrino flux

34. 8/5/2002Ulrich Heintz - Quarknet 200234 observed neutrino flux  ssm = 5.05 +1.01 -0.81  sno = 5.09 +0.44 -0.43 +0.46 -0.43

35. 8/5/2002Ulrich Heintz - Quarknet 200235 neutrino oscillation parameters maximal mixing – sin 2 2  ¼ 1 small  m 2 –  m 2 < 10 -4 eV 2

36. 8/5/2002Ulrich Heintz - Quarknet 200236 accelerator neutrinos LSND (Los Alamos) –  +   + +  –  +  e + + e +  –observe e –oscillations from  Karmen (Rutherford Lab) –no oscillation signal Miniboone (Fermilab) –starts 2002 –will resolve issue

37. 8/5/2002Ulrich Heintz - Quarknet 200237 does it make sense? three oscillation signals –atmospheric neutrinos   m 2 ¼ 10 -3 eV 2 –solar neutrinos   m 2 ¼ 10 -4 eV 2 –accelerator neutrinos   m 2 ¼ 0.1 eV 2 incompatible with three neutrinos –one of the experiments is wrong –there is a 4 th neutrino

38. 8/5/2002Ulrich Heintz - Quarknet 200238 conclusion thank you!

39. 8/5/2002Ulrich Heintz - Quarknet 200239 summary strong evidence for neutrino oscillations –from atmospheric neutrinos (    ?) –from solar neutrinos ( e   or  ?) at least one neutrino must have mass accelerator neutrino oscillation signal –mildly inconsistent experiments –not compatible with these and three neutrinos is there a 4 th (sterile) neutrino?