1. Neutrino physics: The future Gabriela Barenboim TAU04

2. We know that neutrinos are massive and oscillate !

3. e Pure e source Evidence for flavor change Solar neutrinos: Compelling evidence  e +   +    e = 1 3

4. Reactor neutrinos: very strong evidence One pair of parameters fits both solar and reactor data producedsurviving reactor detector 180 km  e 0.6  e

5. Atmospheric neutrinos: Compelling evidence detector Earth   (up)   (down)

6. The hypothesis   with one pair of parameters fits both the atmospheric and accelerator data Expect 106  events in far detector Observe 72   events Accelerator neutrinos: interesting evidence

7. LSND: unconfirmed evidence

8. We do not know how many neutrino mass eigenstates there are. Assuming CPT, confirmation of LSND by MiniBooNE would imply there are more than 3 What have we already learnt ?

9. Neutrinos Required  m 2 solar - reactor 10 -(4-5) atmos.- accelerator 10 -3 LSND 1 eV 2

10. solar - reactor 10 -(4-5) atmos.- accelerator 10 -3 LSND 1 For only three neutrinos   m 2 =(m 3 2 -m 2 2 ) + (m 2 2 -m 1 2 ) + (m 1 2 -m 3 2 ) =0

11.  How many neutrino species are there ? Do sterile neutrinos exist ?

12.  How many neutrino species are there ? Do sterile neutrinos exist ? Let´s assume there are only three neutrinos

13. The neutrino mixing matrix

15.  The unknown oscillation parameters  What is the size of sin 2 (2  13 ) ?  Is there CP violation ?

16.  What is the mass hierarchy ? What is the sign of  m 2 13 ?

17. We determined that m(K L ) > m(K S ) by  Passing kaons through matter (regenerator)  Beating the unknown sign [ m(K L ) –m(K S ) ] against the known sign[reg. ampl.]

18. We determined that m(K L ) > m(K S ) by  Passing kaons through matter (regenerator)  Beating the unknown sign [ m(K L ) –m(K S ) ] against the known sign[reg. ampl.] We will determine the sign(  m 2 13 ) by  Passing neutrinos through matter (Earth)  Beating the unknown sign(  m 2 13 ) against the known sign[forward e e e e ampl]

19. How we are going to do it ? Method 1: accelerator experiments  Appearance experiment  e  Measurement of  e and  e yields  13 and   Matter effects present, baselines of O(100-1000 km)

20. The off axis idea By going off axis, the beam energy is reduced and the spectrum becomes very sharp. Allows an experiments to pick an energy for the maximum oscillation length.

21. . Minakata and Nunokawa What will we get ?

22. . Minakata and Nunokawa What will we get ?

23. Method 2: reactor experiments  Disappearance experiment e x  Clean measurement of  13  No matter effects, baselines O(1 km)

24. Reactor experiments : the future

25. detector 1 detector 2

26. R. McKeown

27.  What is the absolute mass scale ? mass( heavy )

28.  What is the absolute mass scale ?.04 eV < mass( heavy )  m 2 atm

29.  What is the absolute mass scale ?.04 eV < mass( heavy ) <.23 eV  m 2 atm WMAP + 2dFRS + other data  m i <.71 eV

31.  B  c   h m x e ….

32. M.Tegmark

34. .04 eV < mass( heavy ) <.40 eV  m 2 atm If the primordial power spectrum does not have the usually assumed shape,  m i < 1.2 eV  What is the absolute mass scale ?

35. phase space determines energy spectrum transition energy E 0 = E e + E n (+ recoil corrections) experimental observable  – decay kinematics -3 -2 -1 0 E e -E 0 [eV] 1 0.8 0.6 0.4 0.2 0 rel. rate [a.u.] theoretical  spectrum near endpoint m = 0eV m = 1eV dN/dE = K × F(E,Z) × p × E tot × (E 0 -E e ) × [ (E 0 -E e ) 2 – m 2 ] 1/2

36. phase space determines energy spectrum transition energy E 0 = E e + E n (+ recoil corrections) experimental observable  – decay kinematics -3 -2 -1 0 E e -E 0 [eV] 1 0.8 0.6 0.4 0.2 0 rel. rate [a.u.] theoretical  spectrum near endpoint m = 0eV m = 1eV dN/dE = K × F(E,Z) × p × E tot × (E 0 -E e ) × [ (E 0 -E e ) 2 – m 2 ] 1/2 NOT m e

37. 55 KATRIN sensitivity & discovery potential m < 0.2eV (90%CL) m = 0.35eV (5  ) m = 0.3eV (3  ) sensitivity discovery potential expectation: after 3 full beam years  syst ~  stat

38.  What kind of particle is the neutrino ?

39.  Is the neutrino a truly neutral particle ?

40. Why not add a Dirac mass term ? m L R

41. Why not add a Dirac mass term ? m L R This requires R. Then no (SM) principle prevents the occurrence of M C R R

42. Majorana mass Dirac mass (conserves L) from Yukawa couplings (violates L) CP conjugate of left-handed neutrino Right-handed neutrinos

43. Complete See-Saw Mechanism Dirac matrix Heavy Majorana matrix Light Majorana matrix Diagonalise to give effective mass Type II contribution

44. Type I see-saw mechanism Type II see-saw mechanism Types of see-saw mechanism Heavy triplet

45. Naturalness may be over rated … Do this look natural ??

46.  How we can find out ? x p p n n e e SM double weak process 4 body decay: continuos spectrum for the e energy sum

47.  How we can find out ? x p p n n e e SM double weak process 4 body decay: continuos spectrum for the e energy sum x p p n n e e Only allowed for Majorana 2 body decay: e energy sum is a delta

48. i is emitted ( RH + O (m i /E) LH ) Amp[ i contribution]  m i Amp[ 0  ]  |  m i U ei 2 | x p n n e e

49. i is emitted ( RH + O (m i /E) LH ) Amp[ i contribution]  m i Amp[ 0  ]  |  m i U ei 2 | x p n n e e effective neutrino mass

51. m  =|  m i U ei 2 |

52. Cosmology Beta decay Oscillations Double-beta decay

53. “Unexpected” properties  Finite lifetime  Lorentz non-invariance  Magnetic moment  CPT non-invariance

54. Summary We have learned that neutrinos have masses. But we do not know  How many species there are  How much the neutrinos weigh  Whether = We have discovered that two mixing angles are large. But we do not know  The size of the crucial third angle  Whether oscillations violate CP  The spectral pattern

55. Do not miss the neutrino talk at TAU09 !!!