Neutrino Oscillations at Homestakefrom Chlorine to the Megadetector

Ancient Origins of the Question ~1860

Darwin publishes “On The Origin of Species”- &

Kelvin challenges the time scale – The Sun is less than 30 million years – Gravitational Energy

BUT – Kelvin was wrong-The Physics is more interesting

1946-Bruno Pontecorvo described a novel neutrino detector

• Neutrino + 37Cl 37Ar + e-

• ∟ 37Cl + • The Atomic Energy Commission classified

the paper – This detector could be used to locate Nuclear vessels

• But the AEC was WRONG

• The Physics is more interesting e + 37Cl 37Ar + e-

• Reactors emit e

1965-Ray Davis began construction of the Cl Detector to look for e from

HHe fusion in the Sun

1985-The Cl detector observes 2.55 SNU (solar neutrino units)

• The Solar Model (Bahcall) predicts 8 SNU

• signal/prediction = 1/3

• Conclusion: (a) the measurement is wrong, (b) the model is wrong or (c) both are wrong,

• The Conclusion is WRONG –

• The physics is more interesting

Neutrinos Oscillate - 3 species Pontecorvo(1967) & MSW(1985)

• But, Solar Neutrino exps. are complicated –

• unknown source and unknown physics

• Remedy – Use a known source

• Reactors – KAMLAND - e

• Accelerators – Fermilab(& CERN, KEK)- μ

Neutrino Oscillation Fundamentals

• 1) Unoscillated interaction rate ~

• (Beam power) x (Detector Mass)/L2

• 2) Detect & Measure:

• a) Energy distribution of after oscillation

• b) Energy distribution of e due to oscillation

• 3) Backgnd – e from decay of K+ e+ + e

• &e from decay of + e+ ++e

Fermilab Beam Power Options

• 1) Present – 0.7 Megawatts ( of protons)

• 2) SNuMI – 1.2 Megawatts

• 3) Project X – 2.0 Megawatts

Oscillation LengthsFor E = 1 GeV, L23 = 494 km( disappearance) L13

= 15,420km (e appearance)

Thus, e amplitude grows linearly with distance over any Earth based oscillation path.

Signal/uncertainly is L independent since flux varies as 1/L2 and uncertainly as (flux)½.

Since e from K+ and + decays ~1% of flux, want beam path ~ 1/10 L13 or ~ 1500 km. for signal/bkgnd ~ 10.

Large Cavern for Long Base Line Experiment Concept(M. Laurenti)

Finished Cavern

HelicalDrift

Large Cavern for Long Base Line Experiment Concept(M. Laurenti)

Finished Cavern

HelicalDrift

Large Cavern for Long Base Line Experiment Concept(M. Laurenti)

Finished Cavern

HelicalDrift

Large Cavern for Long Base Line Experiment ConceptCross Section

HelicalDrift

4850L

5000L

53M I.D.

85M I.D.

300 kT300 kT Homestake detector and 2 MW and 2 MW generates ~200000 cc evts/yrgenerates ~200000 cc evts/yr

Spectra with 300 kT detector and 2MW beam

from FNAL

• Background Background issues examined issues examined by FNAL/BNL by FNAL/BNL study.study.

NormalNormal ReversedReversed

sin²2θ₁₃= 0.04, 300kT, 1300 km, ~2MW @ 60 GeV 3yrs sin²2θ₁₃= 0.04, 300kT, 1300 km, ~2MW @ 60 GeV 3yrs neutrinosneutrinos and 3yrs antineutrinosand 3yrs antineutrinos

sig~1214sig~1214

sig~394sig~394

sig~564sig~564

sig~564sig~564

sig~627sig~627

Mark Dierckxsens(UChicago), Mary Mark Dierckxsens(UChicago), Mary Bishai(BNL)Bishai(BNL)

Ultimate Reach

Mark Dierckxsens(UChicago), Mary Mark Dierckxsens(UChicago), Mary Bishai(BNL)Bishai(BNL)

Mass Mass orderingordering

θ₁₃θ₁₃

CP ViolationCP Violation60 GeV, 2MW, 3+3 yrs, 300kT60 GeV, 2MW, 3+3 yrs, 300kT

stat+ stat+ 5%syst 5%syst 0.0030.003

0.0070.007

0.0070.007

50% coverage at 3 sigma50% coverage at 3 sigma

Technical issues

•Measure 3-generation parameters without ambiguities. (CP measurement is approximately independent of θ13). Need large detector independent of θ13 value.

•

300 kT water Cherenkov 300 kT water Cherenkov detector @DUSEL detector @DUSEL

Measurement of CP phase and Measurement of CP phase and Sin²2θ Sin²2θ1313 at several points. All at several points. All

ambiguities and mass ambiguities and mass hierarchy are resolved. hierarchy are resolved.

Developing Collaboration

•Proposal for an Experimental Program in Neutrino Physics and Proton Decay in the Homestake Laboratory

This is the This is the author list of author list of hep-ex/06080hep-ex/06080

23 August 23 August 20062006

Other Physics with the Megadetector

• 1) Nucleon decay ~ 1035 years• 2) Supernova prompt neutrinos – • ~105 from SN in the Galaxy• ~10 – 20 from Andromeda• 3) Relic SN neutrinos • 4) Solar neutrinos – sure & HOW• 5) Atmospheric neutrinos – • 6) Also, a great bkgnd shield for • sensitive insert experiments

Nucleon decay•Large body of work

by HyperK, and UNO.

•background levels for the positron+Pion mode

• 3.6/MTon-yr (normal)

• 0.15/MTon-yr (tight)

Expected Sensitivity on K-nu mode is about ~8x10³³ yr Ref: Shiozawa

(NNN05)

300kTX10yrs => 7X10³⁴ yrs

HOPEFULLY

• THE NEW PHYSICS WILL BE MORE

• INTERESTING