Neutrino%20Physics%20-%20Lecture%207

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Neutrino Physics - Lecture 7

• Steve Elliott
• LANL Staff Member
• UNM Adjunct Professor
• 505-665-0068, elliotts_at_lanl.gov

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Lecture 7 Outline

• Accelerator Neutrinos - short - medium baseline
• The neutrinos
• Past experiments
• What we know and what we want to learn
• Most slides from Bill Louis

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The LSND Puzzle and MiniBOONE
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The Evidence for Neutrino Oscillations
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Requires a 3rd ?m2
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Current State of Neutrino Oscillation Evidence
Expt. Type Dm2 (eV2) sin22q LSND nm-gtne
1 3x10-3 Atm. nm-gtnx 2x10-3 1 Solar ne
-gtnx 8x10-5 0.8
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MiniBooNE Neutrino Oscillation Update

• Neutrino Oscillations the 3 ?m2 Problem!?!
  (Sterile Neutrinos?)
• MiniBooNE A Definitive Test of the LSND Neutrino
  Oscillation Signal
• Future Neutrino Experiments BooNE OscSNS

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If MiniBooNE Confirms LSND Physics Beyond the
Standard Model Connections with Astrophysics!
32 Sterile Neutrinos Sorel, Conrad, Shaevitz
(PRD70(2004)073004) Explain Pulsar
Kicks? Explain R-Process in
Supernovae? Explain Dark Matter? MaVaNs
31 Hung (hep-ph/0010126) Sterile
Neutrino Kaplan, Nelson, Weiner
(PRL93(2004)091801) Explain Dark
Energy? CPT Violation 31 Barger, Marfatia,
Whisnant (PLB576(2003)303) Sterile
Neutrino Explain Baryon Asymmetry in the
Universe? Quantum Decoherence Barenboim
Mavromatos (PRD70(2004)093015) Lorentz
Violation Kostelecky Mewes
(PRD70(2004)076002) Katori, Kostelecky,
Tayloe (hep-ph/0606154) Extra Dimensions Pas,
Pakvasa, Weiler (PRD72(2005)095017) Sterile
Neutrino Decay Palomares-Ruiz, Pascoli,
Schwetz (JHEP509(2005)48)
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Probability of Neutrino Oscillations
Pab dab - 4SiSj Uai Ubi Uaj Ubj
sin2(1.27Dmij2L/En)
As N increases, the formalism gets rapidly more
complicated!
N Dmij2 qij CP Phases 2 1
1 0/1 3 2 3 1/3 6
5 15 10/15
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MiniBooNE A Definitive Test of the LSND
Evidence for Oscillations Search for nm -gt ne
Completely different systematic errors than LSND
Much higher energy than LSND Blind Analysis
Alabama, Bucknell, Cincinnati, Colorado,
Columbia, Embry-Riddle, Fermilab, Indiana, Los
Alamos, LSU, Michigan, Princeton, St. Mary's,
Western Illinois, Yale
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(No Transcript)
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MiniBooNE Highlights

• MiniBooNE began taking data in September 2002 and
  has collected 750K neutrino events from 7E20
  Protons on Target Oscillation analysis will use
  600K events from 5.7E20 POT
• Experiment is working well (99 livetime 99 of
  PMT channels working well)
• Clearly reconstructing CCQE, CCPI, NCPI0, NCEL
  events
• First focussing horn was replaced during 2004
  fall shutdown after setting a world record of 96M
  pulses (previous record set at BNL with 13M
  pulses) Second horn now has gt100M pulses
• Now taking data with Antineutrinos (since January
  2006)

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MiniBooNE Neutrino Flux
HARP at CERN E910 at BNL
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Expected MiniBooNE Events
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After ne PID Selection
(from proposal)
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Expected MiniBooNE Sensitivity
(from proposal)
(from proposal)
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Measurement of Oscillation Parameters
(from proposal)
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Likelihoods for Contained NuMI 1 Sub-Events
Good agreement between data and MC!
Preliminary!
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Backgrounds

• Non- ne Backgrounds
• Beam Off
• CC Inclusive
• NC p0
• NC D-gtNg
• NC Coherent g
• NC Radiative g
• Intrinsic- ne Backgrounds
• From m -gt ne decay
• From K-gt ne decay
• From p -gt ne decay

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Beam-Off Background is Negligible!
Neutrino Signal to Cosmic-Ray Background 5000
to 1!
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Good PID Agreement for CC Inclusive Events
Preliminary!
CC inclusive events tagged by Michel
electrons 92 of m- decay 8 of m- capture MC
is correctly estimating CC inclusive background

PID
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MiniBooNE NC p0 Events are Measured
DMp 20 MeV
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Gamma Backgrounds

• NC D-gtNg BR 0.56 at peak small but
  non-negligible background now properly handled
  by modified version of NUANCE
• NC Coherent g Calculated from Rein Sehgal
  (Phys. Lett. 104B (1981) 394) estimated to be
  negligible
• NC Radiative g Two sources have been
  considered, and both are negligible (1)
  Bremsstrahlung Term, where g emanates from recoil
  proton (2) Contact Term, where g emanates from
  the interaction vertex

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Intrinsic ne Backgrounds

• From m -gt ne decay Well determined from nm CCQE
  events
• From K-gt ne decay Measure kaon-induced neutrino
  flux at high energies extrapolate to low
  energies
• From p -gt ne decay Well determined from nm CCQE
  events

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Expectations for 5E20 Protons on Target
Preliminary!
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MiniBooNE Schedule

• Continue Antineutrino Run
• Complete Neutrino Oscillation Analysis (Estimate
  systematic errors from neutrino flux, cross
  sections, detector MC)
• Open Box and Present Results
• If MiniBooNE Confirms LSND gt Physics Beyond the
  Standard Model!

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Future Experiments BooNE OscSNS
What new physics is there Beyond the Standard
Model? BooNE would involve a second
MiniBooNE-like detector (8M) at FNAL at a
different distance with 2 detectors, many of the
systematics would cancel OscSNS would involve
building a MiniBooNE-like detector (12M) with
higher PMT coverage at a distance of 60 m from
the SNS beam stop at ORNL
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BooNE at FNAL
Two identical detectors at different
distances Search for sterile neutrinos via
NCPI0 scattering NCEL scattering Problem
imprecise n energy determination smears
oscillations!
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OscSNS at ORNL
SNS 1 GeV, 1.4 MW
nm -gt ne D(L/E) 3 ne p -gt e n nm -gt ns
D(L/E) lt 1 Monoenergetic nm ! nm C -gt nm
C(15.11)
OscSNS would be capable of making precision
measurements of ne appearance nm disappearance
and proving, for example, the existence of
sterile neutrinos! (see Phys. Rev. D72, 092001
(2005)). Flux shapes are known perfectly and
cross sections are known very well.
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OscSNS nm -gt ne Experiment vs LSND
(assuming Dm2 lt 1 eV2)

• More Detector Mass (x5)
• Higher Intensity Neutrino Source (x2)
• Lower Duty Factor (x100) (less cosmic bkgd)
• No DIF Background (backward direction)
• Lower Neutrino Background (x4) (60 m vs 30 m)
• Better Signal/Background (x4)
• Better L/E Resolution (x2) (more scint better
  PMTs)
• For LSND parameters, expect 350 ne oscillation
  events lt50 background events per year!

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Search for Sterile Neutrinos with OscSNS Via
Measurement of NC Reaction
nm C -gt nm C(15.11) Garvey et al.,
Phys. Rev. D72 (2005) 092001
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KARMEN Measurement of nm C -gt nm C(15.11)
sNC (3.2-0.5-0.4)x10-42 cm2 (B. Armbruster
et al., Phys. Lett. B423 (1998) 15) sNC
2.8x10-42 cm2 (Kolbe, Langanke, Vogel,
Nucl. Phys. A652 (1999) 91)
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Measurement of 32 Model with OscSNS
(Sorel et al., Phys. Rev. D70 (2004) 073004)
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Conclusions

• MiniBooNE will soon test the LSND Oscillation
  Signal
• If the LSND Signal is Confirmed, then Future
  Oscillation Experiments Would Provide a Great
  Opportunity for Neutrino Physics BooNE at FNAL
  OscSNS at ORNLMake Precision Measurements of
  Oscillation Parameters
• Resolve 3 ?m2 Paradox Explore Physics Beyond
  the Standard Model! (e.g. Sterile Neutrinos)