Reactor & Accelerator

Thanks to Bob McKeown for many of the slides

June 2005 Steve Elliott, NPSS 2005 2

Outline

• Reactor NeutrinosThe neutrinosPast experimentsWhat we know and what we want to learn

• Accelerator NeutrinosThe neutrinosPast experimentsWhat we know and what we want to learn

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Distance (m)

P(ee)

€

Pee ≈1− cos4 θ13 1− sin2θ12 sin2 Δm122L

4Eν

⎛

⎝ ⎜

⎞

⎠ ⎟

⎡

⎣ ⎢

⎤

⎦ ⎥

Dominant 12 Oscillation

€

Pee ≈1− sin2 2θ13 sin2 Δm312L

4Eν+

Δm212L

4Eν

⎛

⎝ ⎜

⎞

⎠ ⎟cos4 θ13 sin2 2θ12

Subdominant 13 Oscillation

e Disappearance

June 2005 Steve Elliott, NPSS 2005 4

13

90, 95, 99% CL

hep-

ph/0

3091

30

m232 from SK

atmospheric

Chooz

Solar

122

134

122

134

NCCC sinsinsincos/ ≈+≈ΦΦ

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Neutrino Oscillation Studies with Nuclear Reactors

• e from n-rich fission products

• detection via inverse beta decay (e+pe++n)

• Measure flux and energy spectrum

• Improve detectors, reduce background

• Variety of distances L= 10m-250km

June 2005 Steve Elliott, NPSS 2005 6

Detection Signal

Coincidence signal: detect• Prompt: e+ annihilation EEprompt+En+0.8 MeV• Delayed: n capture 180 s capture time

p+e

511keV

511keV 2.2 MeV

d

n

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June 2005 Steve Elliott, NPSS 2005 8

KamLAND usesthe entire Japanese

nuclear powerindustry as a

long baseline source

Kashiwazaki

Takahama

Ohi

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Solar : m2 = 5.5x10-5 eV2

sin2 2 = 0.833

G.Fogli et al., PR D66, 010001-406,(2002)

Ratio of Measured and Expected e Flux

from Reactor Neutrino Experiments

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Measurement of Energy Spectrum

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KamLAND best fit : m2 = 7.9 x 10-5 eV2

tan2 = 0.45

KamLAND fixes massSolar fixes angle

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New Reactor Proposals

Braidwood, Il

Daya Bay, China

Chooz, France

• ~1.5 km baseline• Deeper/bigger• Near/Far

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Detector Design Studies

horizontal cylinder

horizontal cylinder

spherical

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Oscillation Formulae for Long-Baseline Neutrinos

For anti-neutrinos, the Jcp terms change sign.

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Long Baseline Physics Goals

• Definitive observation of oscillatory behavior in disappearance mode and precise determination of m2

23 and 23.

• Detection of oscillation e in appearance mode and measurement of 13.

• Observe matter effects, hence sign of m223.

• Measure cp

June 2005 Steve Elliott, NPSS 2005 17

CP violation and matter effects

he

p-p

h/0

30

62

21

June 2005 Steve Elliott, NPSS 2005 18

T2K

Phase I0.75 MW +SKPhase II4 MW + HyperK

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HyperK

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NOAUse the NUMI beam line from FermiLab.Far detector uses alternate vertical planes of active scintillator with passive wood absorber.

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Off-Axis Beam• For pions decaying in

flight, most neutrinos are forward directed

• Neutrino energy is proportional to E

• Neutrino energy flattens with angle, however. Allowing one to “choose” an energy by choosing the angle.

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Far Detector810 km from target10-14 km off axis

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LONG baseline 2500-3000 km

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The LSND Puzzle and MiniBOONE

30 meters

e detector

Neutrinose, , and

Protonbeam

Pions

Copper beam stop

Muons and electrons

Watertarget

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The Evidence for Neutrino Oscillations

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Requires a 3rd m2

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Measurement of Oscillation Parameters

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Typical Muon-Neutrino Event

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Typical Michel Electron Event

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Resources

• Bob Mckeown APS April 2005 (Tampa)

• APS neutrino study on reactors and long baseline experiments.

• BNL, T2K and NOA Letters of Intent

• Bill Louis Talks