Neutrino physics : The future

1. Neutrino physics: The future Gabriela Barenboim TAU04

2. We know that neutrinos are massive and oscillate !

3. Evidence for flavor change Solar neutrinos: Compelling evidence ne fne + fnm + fnt 1 = fne Pure ne source 3

4. Reactor neutrinos: very strong evidence reactor detector 180 km produced surviving fne 0.6fne One pair of parameters fits both solar and reactor data

5. Atmospheric neutrinos: Compelling evidence detector fnm(up) = 2 fnm(down) Earth

6. Accelerator neutrinos: interesting evidence 250 km Expect 106 nm events in far detector Observe 72 nm events The hypothesis nm nt with one pair of parameters fits both the atmospheric and accelerator data

7. LSND: unconfirmed evidence + e 30 m + m n n m e n e

8. What have we already learnt ? 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

9. Neutrinos Required Dm2 eV2 solar - reactor 10-(4-5) atmos.- accelerator 10-3 LSND 1

10. solar - reactor 10-(4-5) atmos.- accelerator 10-3 LSND 1 • For only three neutrinos • Dm2=(m32-m22) + (m22-m12) + (m12-m32) =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 sin2(2q13) ? • Is there CP violation?

16. What is the mass hierarchy ? • What is the sign of Dm213 ?

17. We determined that m(KL) > m(KS) by • Passing kaons through matter (regenerator) • Beating the unknown sign[m(KL) –m(KS)] against the known sign[reg. ampl.]

18. We determined that m(KL) > m(KS) by • Passing kaons through matter (regenerator) • Beating the unknown sign[m(KL) –m(KS)] against the known sign[reg. ampl.] We will determine the sign(Dm213) by • Passing neutrinos through matter (Earth) • Beating the unknown sign(Dm213) against the known sign[forward ne e ne e ampl]

19. How we are going to do it ? Method 1: accelerator experiments • Appearance experiment nmne • Measurement of nmne and nm ne yields q13 and d • 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. What will we get ? Minakata and Nunokawa .

22. What will we get ? Minakata and Nunokawa .

23. Method 2: reactor experiments • Disappearance experiment ne nx • Clean measurement of q13 • No matter effects, baselines O(1 km)

24. Reactor experiments : the future

25. Reactor experiments : the future detector 1 detector 2

26. R. McKeown

27. What is the absolute mass scale ? mass(nheavy)

28. What is the absolute mass scale ? .04 eV < mass(nheavy) Dm2atm

29. What is the absolute mass scale ? WMAP + 2dFRS + other data mi < .71 eV .04 eV < mass(nheavy) < .23 eV Dm2atm

31. WB Wc WL h mn xe ….

32. M.Tegmark

33. M.Tegmark

34. What is the absolute mass scale ? If the primordial power spectrum does not have the usually assumed shape,  mi < 1.2 eV .04 eV < mass(nheavy) < .40 eV Dm2atm

35. b – decay kinematics phase space determines energy spectrum transition energy E0 = Ee + En (+ recoil corrections) dN/dE = K × F(E,Z) × p × Etot × (E0-Ee) × [ (E0-Ee)2 – mn2]1/2 theoretical b spectrum near endpoint 1 0.8 0.6 0.4 0.2 0 experimental observable mn = 0eV rel. rate [a.u.] mn = 1eV -3 -2 -1 0 Ee-E0 [eV]

36. b – decay kinematics phase space determines energy spectrum transition energy E0 = Ee + En (+ recoil corrections) dN/dE = K × F(E,Z) × p × Etot × (E0-Ee) × [ (E0-Ee)2 – mn2]1/2 theoretical b spectrum near endpoint 1 0.8 0.6 0.4 0.2 0 NOT mne experimental observable mn = 0eV rel. rate [a.u.] mn = 1eV -3 -2 -1 0 Ee-E0 [eV]

37. KATRIN sensitivity & discovery potential expectation: after 3 full beam years ssyst~sstat mn = 0.35eV (5s) mn = 0.3eV (3s) 5s discovery potential mn < 0.2eV (90%CL) sensitivity

38. What kind of particle is the neutrino ?

39. What kind of particle is the neutrino ? • Is the neutrino a truly neutral particle ?

40. Why not add a Dirac mass term ? m nLnR

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

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

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

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

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

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

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

48. ni is emitted ( RH + O(mi/E) LH ) p n Amp[ni contribution]  mi e n x n e n Amp[0nbb] | mi Uei2|

49. ni is emitted ( RH + O(mi/E) LH ) p n Amp[ni contribution]  mi e n x n e n Amp[0nbb] | mi Uei2| effective neutrino mass