ne Appearance Experiment with Offaxis Detector in a NuMI Beam

1
ne Appearance Experiment with Off-axis Detector
in a NuMI Beam

• Physics
• Off-axis NuMI Beam
• Detector Issues
• Off-axis Experiments evolution of the
  accelerator and detectors
• Scenarios

February 15, 2003 Adam Para
2
Neutrinos vs Standard Model

• Whereas
• There is a major effort to complete the Standard
  Model (Higgs search)
• There is a broad front of experiments looking for
  possible deviations from the Standard Model (SUSY
  searches, B-physics experiments, g-2, EDM, )
• The first evidence for physics beyond the
  standard model is here
• Neutrino mass and oscillations
• Where does it lead us?
• Just an extension (additional 9? 7? Parameters) ?
• First glimpse at physics at the unification scale
  ? (see-saw??)
• Extra dimensions?
• Unexpected? (CPT violation ???)

3
The outstanding questions in neutrino physics,
AD2003

• Neutrino mass pattern This ?
  Or that?

• Electron component of n3 (sin22q13)

• Complex phase of s ?? CP violation in a neutrino
  sector ?? (?) baryon number of the universe

• mixing angle q23 sin22q23 1 e New
  symmetry? Broken?

4
The key nm ? ne oscillation experiment

3 unknown, 2 parameters under control,
neutrino/antineutrino
5
Anatomy of Bi-probability ellipses

• Minakata and Nunokawa, hep-ph/0108085

cosd

• Observables are
• P
• P
• Interpretation in terms of sin22q13, d and sign
  of Dm223 depends on the value of these parameters
  and on the conditions of the experiment L and E

• d

sind
sin22q13
Rates differ by factor of 4 for the same sin22q13
6
Mass Textures and q13 Predictions, Examples
Altarelli,Feruglio, hep-ph/0206077
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Off-axis NuMI Beams unavoidable byproduct

• Beam energy defined by the detector position
  (off-axis, Beavis et al)
• Narrow energy range (minimize NC-induced
  background)
• Simultaneous operation (with MINOS and/or other
  detectors)
• 2 GeV energy
• Below tau threshold
• Relatively high rates per proton, especially for
  antineutrinos
• Matter effects to amplify to differentiate mass
  hierarchies
• Baselines 700 1000 km

8
Oscillation probability vs physics parameters
Parameter correlation even very precise
determination of Pn leads to a large allowed
range of sin22q23 ? antineutrino beam is more
important than improved statistics
9
ne Appearance Counting Experiment a Primer
This determines sensitivity of the experiment

• Systematics
• Know your expected flux
• Know the beam contamination
• Know the NC backgroundrejection power (Note
  need to beat it down below the level of ne
  component of the beam only)
• Know the electron ID efficiency

10
Sources of the ne background
ne/nm 0.5
All
K decays

• At low energies the dominant background is from
  m?enenm decay, hence
• K production spectrum is not a major source of
  systematics
• ne background directly related to the nm spectrum
  at the near detector

11
NuMI Off-axis Detector

• Low Z imaging calorimeter
• Glass RPC or
• Drift tubes or
• Liquid or solid scintillator
• Electron ID efficiency 40 while keeping NC
  background below intrinsic ne level
• Well known and understood detector technologies
• Primarily the engineering challenge of (cheaply)
  constructing a very massive detector
• How massive??
• 50 kton detector, 5 years run gt
• 10 measurement if sin22q13 at the CHOOZ limit,
  or
• 3s evidence if sin22q13 factor 10 below the CHOOZ
  limit (normal hierarchy, d0), or
• Factor 20 improvement of the limit

12
Signal and background

Clean track muon (pion)
Fuzzy track electron
13
Background examples
NC - p0 - 2 tracks
nm CC - with p0 - muon
14
Beam-Detector Interactions

• Optimizing beam can improve signal
• Optimizing beam can reduce NC backgrounds
• Optimizing beam can reduce intrinsic ne
  background
• Easier experimental challenge, simpler detectors
• of events proton intensity x detector mass
• Allocate the reources to maximize the product,
  rather than individual components

15
A Quest for NuMI Proton Intensity
NuMI Intensity Working Group, D. Michael/P. Martin
Nominal NuMI year
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Two phase program

• Phase I ( 100-200 M, running 2007 2014)
• 50 kton (fiducial) detector with e35-40
• 4x1020 protons per year
• 1.5 years neutrino (6000 nm CC, 70-80
  oscillated)
• 5 years antineutrino (6500 nm CC, 70-80
  oscillated)
• Phase II ( running 2014-2020) (D. Harris)
• 200 kton (fiducial) detector with e35-40
• 20x1020 protons per year (new proton source?)
• 1.5 years neutrino (120000 nm CC, 70-80
  oscillated)
• 5 years antineutrino (130000 nm CC, 70-80
  oscillated)

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Conclusions

• Neutrino Physics is an exciting field for many
  years to come
• Most likely several experiments with different
  running conditions will be required to unravel
  the underlying physics
• Fermilab/NuMI beam is uniquely matched to this
  physics in terms of beam intensity, flexibility,
  beam energy, and potential source-to-detector
  distances that could be available
• Important element of the HEP program in the US
  for the next 20 years

18
Project Evolution (so far)

• May 2002 Workshop ot Fermilab, 140 people
• June 2002 LOI submitted
• September 2002 All about NuMI UCL London, 27
  participants
• Now Argonne- Athens - Berkeley - Boston -
  Caltech - Chicago - College de France - Fermilab
  -Harvard - ITEP - Lebedev - UC-London - LSU - MIT
  - MSU Minnesota-Crookstone - Minnesota-Duluth
  -Minnesota-Minneapolis - TUM-Munchen - NIU -
  Ohio-Athens - Oxford - Pittsburgh - Princeton -
  Rochester - Rutherford - Sao Paulo - Stanford -
  Stony Brook - Sussex- Texas-Austin - TMU-Tokyo -
  Tufts - UCLA - Virginia Tech - York-Toronto(115
  physicists) (red joined since LOI submission)
• Expression of interest from several more
  institutions
• January 2003 Detector Workshop at SLAC 65
  people, narrow technologies to sampling
  calorimeters
• April 2003 Detector Workshop at Argonne, compare
  gas/scintillator detector designs

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What size collaboration is needed to construct
and do physics with the detector? Do the
collaborators have other, overlapping
obligations ?

• The detector is huge but simple. The size of the
  technical/engineering staff is the most critical
  for for the timely design/construction/installatio
  n of the experiment.
• At present there are some 45 institutions, 140
  physicists involved. More groups are expressing
  their interest.
• While most people have, to a varying degree,
  other obligations at this time, the strength of
  the collaboration already now is sufficient to
  ensure a success of the experiment.
• We expect a significant influx of interested
  parties once the project becomes more real.

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What is the timeline/schedule for the Off-Axis
beam and detector?

• NuMI beam start operation spring 2005 (Reminder
  a major investment of US High Energy Physics)
• Detector construction schedule driven by
  external factors. An optimistic scenario
• Oct 03 proposal
• fall 03 - spring 04 initial reviews, cost and
  design validation
• summer 04 - approval
• 04 - 05 construction of a near detector,
  preparation of infrastructure for mass production
• 05 site selection, start site preparation
• 06 start construction
• 07 start data taking with adiabatically growing
  detector
• 08 complete construction

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What is the estimated project cost including the
beam and detector? Please give the basis for
the cost estimate.

• Beam exists. Three-fold intensity upgrades is
  estimated to cost 45M.Based of on the work of
  the joint Beams Division/NuMI/MINOS working
  group.
• A committee dedicated to the review, validation
  and specific recommendation is being formed.
•  
• Detector costs are based on the existing
  experience of MINOS and other experiments, like
  BELLE, using the same technology. An estimated
  detector cost is in the range of 1-3 M per kton.
  
• Large cost savings can be accomplished by
  optimization of the longitudinal sampling. The
  current cost estimates assume 1/3 radiation
  length sampling which provides a very comfortable
  background rejection. Need a complete validated
  design to have a credible cost estimate

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How does the Off-Axis Detector fit into the
evolving world picture, especially the
JHF-SuperK experiment, in terms of adding an
important new contribution to ourunderstanding
of particle physics?

•  
• Determination of the neutrino mixing matrix, mass
  hierarchy, possible studies of CP violation will
  require multiple precise measurements taken under
  different conditions (distance, energy, matter
  effects).
• In principle, the NuMI beam provides enough
  flexibility to complete the entire program, given
  a sufficienty large number of massive detectors
  located at different positions. This would be a
  very long, and very expensive program.
• Parallel measurements at JHF, with no matter
  effects, will help to extract the interesting
  physics parameters in a shorter (still probably
  very long) time scale.
• A possible new reactor experiment
  measuring/further limiting q13 would be a great
  help in reducing the correlations between the
  parameters of interest.
•  

23
Determination of mass hierarchy complementarity
of JHF and NuMI
Combination of different baselines NuMI JHF
extends the range of hierarchy discrimination to
much lower angles mixing angles
Minakata,Nunokawa, Parke
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Two body decay kinematics
At this angle, 15 mrad, energy of produced
neutrinos is 1.5-2 GeV for all pion energies ?
very intense, narrow band beam

• On axis En0.43Ep