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