NEUTRINO MASSES AND OSCILLATIONS Triumphs and Challenges

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NEUTRINO MASSES AND OSCILLATIONSTriumphs and
Challenges
R. D. McKeown Caltech
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Outline

• Historical introduction
• Neutrino Oscillations
• Vacuum Oscillations
• Matter Oscillations

• Neutrino Masses
• The Near Future
• Outlook

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Historical Perspective
UP CHARM TOP
DOWN STRANGE BOTTOM
ELECTRON ne MUON nm TAU nt
n1 n2 n3
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New Periodic Table
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Discovery of the Neutrino 1956
F. Reines, Nobel Lecture, 1995
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EarlyHistory

• 1936- discovery of the muon
• (I. Rabi Who ordered that ??)
• 1950s - discovery of ns at nuclear reactors
• 1958 B. Pontecorvo proposes neutrino
  oscillations
• 60s and 70s n were studied with accelerator
  experiments ne ? nm

"All you have to do is imagine something that
does practically nothing. You can use your
son-in-law as a prototype."
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More Recent History

• 1968 1st solar n anomaly evidence
• 1980s new interest in neutrino masses and
  oscillations
• ns as dark matter??
• 1980-present the quest for neutrino oscillations
• 1998 Super-Kamiokande obtains first evidence for
  neutrino oscillations

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Two Generation Model
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Length Energy Scales
Super-K!!
En 1 GeV, Dm210-3 eV2 , L 1240 km
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30 kton H20 Cherenkov 11000 20 PMTs
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Super-Kamiokande Results
Wn gt 0.001
g K2K, MINOS
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Length Energy Scales
Super-K
En 1 GeV, Dm210-3 eV2 , L 1240 km
Chooz, Palo Verde
En 1 MeV, Dm210-3 eV2 , L 1.2 km
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Reactor Neutrino Experiments

• ne from n-rich fission products
• detection via inverse beta decay (nepgen)
• Measure flux and energy spectrum
• Variety of distances L 10-1000 m

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Precise Measurements
Flux and Energy Spectrum g 1-2
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Early Reactor Oscillation Searches
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Distance (m)
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Enter

• Long Baseline (180 km)
• Calibrated source(s)
• Large detector (1 kton)
• Deep underground (2700 mwe)

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Length Energy Scales
Super-K
En 1 GeV, Dm210-3 eV2 , L 1240 km
Chooz, Palo Verde
En 1 MeV, Dm210-3 eV2 , L 1.2 km
En 1 MeV, Dm210-5 eV2 , L 125 km
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Designed to test solar neutrino oscillation
parameters on Earth (!) KamLAND has a much
longer baseline than previous (reactor)
experiments
Statistical errors only
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Only a few places in the World could host an
experiment like KamLAND
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KamLAND uses the entire Japanese nuclear
power industry as a longbaseline source
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Narrow baseline range 85.3 of signal has 140
km lt L lt 344 km

• The total electric power produced as a
• by-product of the ns is
• 60 GW or...
• 4 of the worlds manmade power or
• 20 of the worlds nuclear power

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Spectrum Distortion
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KamLAND Detector
1000 Ton
(135 mm)
1879
(Cosmic veto)
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Selecting antineutrinos, Epromptgt2.6MeV
5.5 m fiducial cut

• - Rprompt, delayed lt 5.5 m
• - ?Re-n lt 2 m
• - 0.5 µs lt ?Te-n lt 1 ms
• 1.8 MeV lt Edelayed lt 2.6 MeV
• 2.6 MeV lt Eprompt lt 8.5 MeV
• Tagging efficiency 89.8

(543.7 ton)
Balloon edge

• In addition
• 2s veto for showering/bad µ
• 2s veto in a R 3m tube along track
• Dead-time 9.7

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Ratio of Measured and Expected ne Flux from
Reactor Neutrino Experiments
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Measurement of Energy Spectrum
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Oscillation Effect
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KamLAND best fit Dm2 7.9 x 10-5 eV2 tan2q
0.45
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Solar Neutrino Energy Spectrum
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More missing neutrinos
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Neutrino Oscillations?
Rorbit
Just So ???
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Length Energy Scales
Super-K
En 1 GeV, Dm210-3 eV2 , L 1240 km
Chooz, Palo Verde
En 1 MeV, Dm210-3 eV2 , L 1.2 km
En 1 MeV, Dm210-5 eV2 , L 125 km
En 1 MeV, Dm210-11 eV2 , L 108 km
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Matter Enhanced Oscillation (MSW)
Mikheyev, Smirnov, Wolfenstein
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Enter SNO
ne d g p p e- ( CC )
nx d g p n nx ( NC )
nx e- g nx e- ( ES )
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Combined fit with solar neutrino data
Dm27.90.6-0.5x10-5 eV2 tan2q0.400.10-0.07
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Open circles combined best fit Closed circles
experimental data
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RECENT NEWSMiniBOONE refutes LSND!
LSND ruled out at 98 confidence
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Maki Nakagawa Sakata Matrix
Future Reactor Experiment!
CP violation
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lt
Why so different???
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New Periodic Table
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The Mass Puzzle
Seesaw mechanism
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Why havent we seen nR?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)
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The Quest for q13at the Daya Bay Nuclear
Power Plant

• Baseline 2km
• More powerful reactors
• Multiple detectors ? measure ratio

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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

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DYB NPP region Location and surroundings
55 km
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Experiment Layout
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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 8PMT/module
• Photocathode coverage
• 5.6 ? 12(with reflector)

20 t Gd-LS
LS
oil
Target 20 t, 1.6m g-catcher 20t, 45cm Buffer
40t, 45cm
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Sensitivity to Sin22q13

90 CL, 3 years

• Experiment construction 2008-2010
• Start acquiring data 2010
• 3 years running

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Goals for the future

• Establish q13 non-zero
• Measure CP violation
• Determine mass hierarchy

Also Majorana or Dirac Sterile species?
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ne Appearance
T2K- From Tokai To Kamioka
CP violation
matter
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NOnA - New Fermilab Proposal
L 810 km
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Parameters Consistent with a 1 and 4 nm?ne
oscillation probability
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Daya Bay will complement NOnA
normal
Daya Bay
dCP
inverted
NOnA (5 yr n)
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FNALto Homestake
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Neutrino Factory -- CERN layout
1016p/s
1.2 1014 m/s 1.2 1021 m/yr
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0.9 1021 m/yr
m ? e ne nm
3 1020 ne/yr 3 1020 nm/yr
oscillates ne ? nm interacts giving m- WRONG
SIGN MUON
interacts giving m
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Beta Beams
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Other Future Studies

• Double beta decay (mlt0.1 eV)
• (Majorana only!)
• Direct measurements (mlt 1 eV)
• (KATRIN)
• Cosmological Input (mlt0.2 eV)
• (Planck satellite)

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My prediction

• We will measure

• neutrino mass hierarchy

• CP violation in n mixing

And know the role of ns in

• particle physics

• cosmology

All in time for Keh-Feis 70th !!
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Happy Birthday Keh-Fei !!