reνolution Three Neutrino Oscillation Lecture Two Lindley Winslow Massachusetts Institute of Technology

Transcription

1 reνolution Three Neutrino Oscillation Lecture Two Lindley Winslow Massachusetts Institute of Technology 1

2 The neutrino is neutral. The neutrino only interacts weakly. The neutrino has a small non-zero mass. 2

3 From Yesterday s Lecture 3

4 n p + e- + νe νe 4

5 5

6 6

7 νe 7

8 8

9 9

10 Atmospheric Neutrinos from above cosθ=1 from below cosθ= -1 10

11 Things are about to get interesting...

12 ! µ" #"! 2" #"! e!! 1! Two neutrino mixing determined by one mixing angle and and one mass difference squared. 12

13 13 Three neutrino mixing will be defined by three mixing angles and two independent mass differences.

14 Factor the Matrix 14

15 Atmospheric/Accelerator Schwetz et al. arxiv:

16 Solar/KamLAND Schwetz et al. arxiv:

17 ? What do we know about this third mixing angle? 17

18 18

19 The Full Reactor Antineutrino Survival Probability E=3MeV sin 2 2θ13 ~ 0.2 Δm31 2 = ev 2 19

20 To be Sensitivity to θ13 you need to be closer... E=3MeV sin 2 2θ13 ~ 0.2 Δm31 2 = ev 2 20

21 Do not look at the blue line... The best fit comes from Chooz, sin 2 2θ13 < 0.16, and putting together everything sin 2 2θ13 ~

22 Our Current Knowledge Schwetz et al. arxiv:

23 We have seen this before... CC u c! t! d s! b! is actually u c! t! d s! b This is the famous CKM Matrix that describes the quark mixing. 23

24 This is Quark Mixing (! )! 24

25 This is Quark Mixing This is Neutrino Mixing (! )! (! )! 25

26 ? What is that thing hanging around with the θ13? 26

27 What is CP Violation? or 27

28 28 From H. Murayama

29 One rule we hold dear... CPT Conservation or CPT conservation is all mixed together with the Lorentz invariance, locality and causality of your theory, so we do not like to mess with it. 29

30 Disappearance Experiments... CPT and CP are the same condition. or So you can never detect plain CP violation in a disappearance experiment. 30

31 We need an appearance experiment.

32 Appearance Probability in Vacuum: There are mass splitting terms 32

33 Appearance Probability in Vacuum: There are mixing angle terms. 33

34 Appearance Probability in Vacuum: And there are terms for the CP violating phase which is really what we want to go after... 34

35 Visualizing the effect of the CP phase... P osc (! " #! $ )! %& 0 '& CP CP parameter! P osc (! " #! $ )! 35

36 First Approach: A Beam

37 An Example Neutrino Beamline Choose a Pion... Look here for νe. Look here for νe. 37

38 You want the biggest effect possible... Maximize This! standard beam energy is 1GeV atmospheric Δm 2 is ~0.001 ev 2 Your beam needs to go 1,000km! 38

39 Fermilab to South Dakota, Go West Little Neutrinos! 39

40 Long Baseline Neutrino Experiment LBNE

41 Getting a beam to South Dakota... 41

42 Remember that MSW effect for neutrinos going through matter. P osc (! " #! $ )! %& 0 '& CP CP + matter, CP parameter! P osc (! " #! $ )! Matter will effect only neutrinos so this is a type of CP violation but not the effect we want to measure! 42

43 And we have been kind of ignoring something... Kayser and Parke

44 44 Kayser and Parke 2009

45 CP + matter, %&m 2 <0 P osc (! " #! $ )! '% CP CP + matter, &m 2 >0 So in order to interpret data you will need to model the matter between FermiLab and South Dakota. P osc (! " #! $ )! 45

46 A Detector... 46

47 Take Super-K and multiply X 2 Then Build N Detectors. For now N=2. 47

48 Liquid Argon is super cool... Proposals for multi-kton LAr detectors are in the running, but I will focus on the water Cerenkov Detector. 48

49 Looking for Charge Current Interactions... 49

50 And our desired reaction... νe e - 50

51 From Yesterday: A Wimpy 8 MeV Solar Neutrino in Super-K

52 A 603MeV muon in Super-K. 52

53 A 492MeV electron in Super-K. It s a bit fuzzier. 53

54 Anti-neutrinos are harder to detect and make. And your beam is a bit dirty... 54

55 This is what we know... 55

56 Now let s pretend... Your sensitivity contours kind of look like a jelly bean. 56

57 Ten years of running LBNE, If the hierarchy is normal and there are no upgrades to the FermiLab beam. A lot of different jelly beans to choose from... 57

58 Second Approach: Multiple Cyclotrons

59 DAE!ALUS 59

60 60

61 61

62 The basic idea is the same... 62

63 But Now... They are stackable. And possibly hug-able... They are super conducting. 63

64 What we want is a decay at rest beam (DAR)... P Pions! Dump neutrinos No νe! These are harder to make and the μ - capture. 64

65 And here is the idea... osc max (!/2)! at 40 MeV! off max (!/4)! at 40 MeV! Constrains! flux! 20km! 8km! 1.5km! A multiple-baseline,! single-detector! experiment! free! protons! Re-use your gigantic detector! 65

66 And with the multiple baselines... You can use the interference between the terms to pull out the magnitude of the CP effect. 66

67 And you saw this trick before... Anti-Neutrino Detection - Inverse Beta Decay e+ ν e p Event #1 Ee = Eν - 0.8MeV n 30μs Event #2 Eγ~8MeV Gd 67 p

68 Two backgrounds, invisible muons from atmospheric neutrinos... and the diffuse supernova background. 68

69 Near With 10 years of running... Middle Far 69

70 We can measure CP Violation! Daedalus Phase

71 By Construction our performance is similar to LBNE, Daedalus Phase LBNE 5 yrs nu + 5 yrs nubar but the systematic uncertainties are completely different! 71

72 Working together is always better... With Different interactions, Different beams, Different energies, We beat down the systematic uncertainties and We win! 72

73 73

74 They have decided to have tiny masses. (! )! vs. (! )! They have decided to have large mixing. vs. Why not an inverse hierarchy and large CP violation? 74

75 The race is on for θ13...

76 A little more about the cyclotrons... 76

77 77

78 Choosing your proton energy, a goldilocks problem... Just Right Not Enough Too Much 78

79 79

80 80 Kayser and Parke 2009

81 81