NEUTRINO MASSES AND OSCILLATIONS NEUTRINO MASSES AND OSCILLATIONS Triumphs and Challenges R. D. McKeown Caltech
Jan 17, 2016
NEUTRINO MASSES AND NEUTRINO MASSES AND OSCILLATIONSOSCILLATIONS
Triumphs and Challenges
R. D. McKeownCaltech
OutlineOutline
• Historical introduction• Neutrino Oscillations
Vacuum OscillationsMatter Oscillations
• Neutrino Masses
• The Near Future
• Outlook
1869
Historical Perspective
UP CHARM TOP
DOWN STRANGE BOTTOM
ELECTRON
e
MUON
TAU
1913
???1 2 3
New “Periodic Table”
Discovery of the Neutrino – 1956
F. Reines, Nobel Lecture, 1995
EarlyHistory
• 1936- discovery of the muon (I. Rabi: Who ordered that ??)
• 1950’s - discovery of ’s at nuclear reactors
• 1958 – B. Pontecorvo proposes neutrino oscillations
• 60’s and 70’s – were studied with accelerator experiments e ≠
"All you have to do is imagine something that does practically nothing. You can use your son-in-law as a prototype."
More Recent History
• 1968 – 1st solar anomaly evidence
• 1980’s – new interest in neutrino masses and oscillations:
’s as dark matter??
• 1980-present: the quest for neutrino oscillations
• 1998 Super-Kamiokande obtains first evidence for neutrino oscillations
Two Generation Model
1.24
(Pe minimum)
Length & Energy Scales
E= 1 GeV, m2=10-3 eV2 , L = 1240 km Super-K!!
1.24
(Pe minimum)
30 kton H20 Cherenkov 11000 20” PMT’s
Super-Kamiokande Results
Neutrino Oscillation Interpretation
K2K, MINOS
> 0.001
Length & Energy Scales
E= 1 GeV, m2=10-3 eV2 , L = 1240 km
E= 1 MeV, m2=10-3 eV2 , L = 1.2 km
Super-K
Chooz,Palo Verde
1.24
(Pe minimum)
Reactor Neutrino Experiments
• e from n-rich fission products• detection via inverse beta decay (e+pe++n)• Measure flux and energy spectrum• Variety of distances L= 10-1000 m
Precise Measurements
Flux and Energy Spectrum ~1-2 %
Early Reactor Oscillation Searches
103
Distance (m)
Enter
• Long Baseline (180 km)• Calibrated source(s)• Large detector (1 kton)• Deep underground (2700 mwe)
Length & Energy Scales
E= 1 GeV, m2=10-3 eV2 , L = 1240 km
E= 1 MeV, m2=10-3 eV2 , L = 1.2 km
E= 1 MeV, m2=10-5 eV2 , L = 125 km
Super-K
Chooz,Palo Verde
1.24
(Pe minimum)
Stat
istic
al e
rror
s on
ly
Designed to test solar neutrino
oscillation parameters
on Earth (!)KamLAND has a much
longer baselinethan previous
(reactor) experiments
Only a few places in the World could hostOnly a few places in the World could hostan experiment like KamLAND…an experiment like KamLAND…
KamLAND usesthe entire Japanese
nuclear powerindustry as a
long baseline source
Kashiwazaki
Takahama
Ohi
Narrow base
line
Narrow base
line
range:
range:
85.3% of signal h
as
85.3% of signal h
as
140 km < L <
344
140 km < L <
344
kmkmThe total electric power produced “as a The total electric power produced “as a by-product” of the by-product” of the ’s is:’s is:
•~60 GW or...~60 GW or...•~4% of the world’s manmade power or…~4% of the world’s manmade power or…•~20% of the world’s nuclear power~20% of the world’s nuclear power
Spectrum Distortion
KamLAND Detector
1879
1000 Ton
(Cosmic veto)
(135 m)
- R- Rprompt, delayedprompt, delayed < 5.5 m < 5.5 m
- - ΔΔRRe-ne-n < 2 m < 2 m
- 0.5 - 0.5 μμs < s < ΔΔTTe-ne-n < 1 ms < 1 ms
- 1.8 MeV < E1.8 MeV < Edelayeddelayed < 2.6 MeV < 2.6 MeV
- 2.6 MeV < E2.6 MeV < Epromptprompt < 8.5 MeV < 8.5 MeV
Tagging efficiency 89.8%Tagging efficiency 89.8%
… …In addition:In addition:
- 2s veto for showering/bad 2s veto for showering/bad μμ
- 2s veto in a R = 3m tube along track2s veto in a R = 3m tube along track
Dead-time 9.7%Dead-time 9.7%
Selecting antineutrinos, ESelecting antineutrinos, Epromptprompt>2.6MeV>2.6MeV
(543.7 ton)(543.7 ton)
5.5 m5.5 mfiducial cutfiducial cut
Balloon edgeBalloon edge
Ratio of Measured and Expected e Flux from Reactor Neutrino Experiments
Solar : m2 = 5.5x10-5 eV2
sin2 2 = 0.833
G.Fogli et al., PR D66, 010001-406,(2002)
Measurement of Energy Spectrum
Oscillation Effect
KamLAND best fit : m2 = 7.9 x 10-5 eV2
tan2= 0.45
Solar Neutrino Energy Spectrum
More missing neutrinos…
Neutrino Oscillations?
Rorbit
“Just So ??? “
Length & Energy Scales
E= 1 GeV, m2=10-3 eV2 , L = 1240 km
E= 1 MeV, m2=10-3 eV2 , L = 1.2 km
E= 1 MeV, m2=10-5 eV2 , L = 125 km
Super-K
Chooz,Palo Verde
1.24
(Pe minimum)
E= 1 MeV, m2=10-11 eV2 , L = 108 km
Matter Enhanced Oscillation (MSW)Mikheyev, Smirnov, Wolfenstein
Enter SNO…e + d p + p + e- ( CC )
x + d p + n + x ( NC )x + e- x + e- ( ES )
• Neutrino Mixing• Neutrino Masses• Flavor Oscillations
+
Combined fit with solar neutrino data
m2=7.9+0.6-0.5x10-5 eV2
tan2=0.40+0.10-0.07
Open circles: combined best fitClosed circles: experimental data
RECENT NEWSMiniBOONE refutes LSND!
LSND ruled out at 98% confidence
Maki – Nakagawa – Sakata Matrix
Future ReactorExperiment!
CP violation
Why so different???Why so different???
<
New “Periodic Table”
L R mD
mD M
LR
m mD
2
MmD
“Seesaw mechanism”
M
The Mass PuzzleThe Mass Puzzle
Why haven’t we seen R?Extra Dimension
• All charged particles are on a 3-brane• Right-handed neutrinos SM gauge singlet
Can propagate in the “bulk”• Makes neutrino mass small
(Arkani-Hamed, Dimopoulos, Dvali, March-Russell;Dienes, Dudas, Gherghetta)
• Barbieri-Strumia: SN1987A constraint“Warped” extra dimension (Grossman, Neubert)
or more than one extra dimensions• Or SUSY breaking
(Arkani-Hamed, Hall, HM, Smith, Weiner;
Arkani-Hamed, Kaplan, HM, Nomura) (From H.Murayama)
• Baseline ~2km
• More powerful reactors
• Multiple detectors → measure ratio
The Quest for 13
at the Daya Bay
Nuclear Power Plant
• 4 reactor cores, 11.6 GW
• 2 more cores in 2011, 5.8 GW
• Mountains provide overburden to shield cosmic-ray backgrounds
Daya Bay nuclear power plant
DYB NPP region
Location and surroundings
55 km
Experiment Layout
Detector modules
• Three zone modular structure: I. target: Gd-loaded scintillator
II. g-catcher: normal scintillator
III. Buffer shielding: oil
• Reflector at top and bottom• 192 8”PMT/module• Photocathode coverage: 5.6 % 12%(with reflector)
20 t Gd-LS
LSoil
Target: 20 t, 1.6mg-catcher: 20t, 45cmBuffer: 40t, 45cm
Sensitivity to Sin22q13
• Experiment construction: 2008-2010• Start acquiring data: 2010• 3 years running
90% CL, 3 years
Goals for the future
• Establish 13 non-zero
• Measure CP violation
• Determine mass hierarchy
Also: Majorana or Dirac Sterile species?
e Appearance
CP violation
matter
T2K- From Tokai To Kamioka
Mass hierarchy (+/-)
L = 810 km
NOA - New Fermilab Proposal
Parameters Consistent with a1% and 4% e oscillation probability
NOA(5 yr )
Daya Bay
CP
normal
inverted
Daya Bay will complement NOA
FNALto Homestake
Neutrino Factory -- CERN layout
e+ e
_
interacts
giving
oscillates e
interacts giving
WRONG SIGN MUON
1016p/s
1.2 1014 s =1.2 1021 yr
3 1020 eyr
3 1020 yr
0.9 1021 yr
Beta Beams
Other Future StudiesOther Future Studies
• Double beta decay (m<0.1 eV)(Majorana only!)
• Direct measurements (m< 1 eV) (KATRIN)
• Cosmological Input (m<0.2 eV) (Planck satellite)
My prediction:My prediction:We will measure:
• neutrino mass hierarchy
• CP violation in mixing
And know the role of ’s in• particle physics
• cosmology
All in time for Keh-Fei’s 70All in time for Keh-Fei’s 70thth !! !!