E1 Working Group Neutrino Factories and Muon Colliders

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E1 Working GroupNeutrino Factories and Muon
Colliders

• Ingredients Todd Adams, Carl Albright, Mayumi
  Aoki, Valeri Balbekov, Richard Ball, Vernon
  Barger, Mike Berger, Mario Campanelli, Dave
  Casper, Weiren Chou, Dave Cline, Priscilla
  Cushman, Fritz DeJongh, Milind Diwan, Bonnie
  Fleming, Al Garren, Steve Geer, Gail Hanson,
  Debbie Harris, Atsuko Ichikawa, Carol Johnstone,
  Steve Kahn, Boris Kayser, Chiang Kee Jung, Bruce
  King, Yoshitaka Kuno, Manfred Lindner, Shinji
  Machida, Bill Marciano, Kirk McDonald, Kevin
  McFarland, Jorge Morfin, Nikolai Mokhov, Bill
  Molzon, Bill Morse, Ken Nagamine, Tsuyoshi
  Nakaya, David Neuffer, Yasuhiro Okada, Fred
  Olness, Robert Palmer, Zohreh Parsa, Bernard
  Pope, Stefano Rigolin, Lee Roberts, Andrea
  Romanino, Thomas Roser, Akira Sato, Heidi
  Schellman, Masato Shiozawa, Bob Shrock, Hank
  Sobel, Panagiotis Spentzouris, Ed Stoeffhaus,
  Larry Wai, Yi Fang Wang, Koji Yoshimura, Jae Yu,
  Mike Zeller and many other enthusiastic folks
• ?? ?? ?? ?? ?? ?? ??
• PHYSICS TO ADDRESS
• Neutrino Oscillations Conventional Beams
• Intense Muon Source Physics
• The Rest of Neutrino Physics (non-oscillation)
• Neutrino Oscillations Muon Storage Rings
• Muon Collider Physics

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SNO Results

• After a long history of solar neutrino anomaly
  results, SNO is confirming that the discrepancy
  is due to neutrino physics and not the solar
  model
• ne from the Sun become ne and (nm , nt)

K. Heeger, Les Houches 01
3
SuperKamiokande Results

• Again, after a long history of anomalous
  results, the atmospheric neutrino data are
  indicating oscillations

K. Nishikawa, NuFact01
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We are in the middle of a fundamental discovery!

• Neutrinos have mass, and mn/mtop lt 10-14
• Oscillations can
• Give insight into the theory of flavor what
  makes a generation a generation?
• Tell us about the origin of fermion masses
• Suggest a high mass scale of new physics
• Contribute to understanding the origin of baryon
  asymmetry in the universe
• This is one of precious few windows onto Grand
  Unified Theories linking quark and lepton sectors.

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What do we know today?

• nm made in the atmosphere are disappearing
  stronger and stronger indications that they are
  becoming nt, not ns
• Dmatm2? 3x10-3eV2
• ne made in the sun are disappearing 3s
  indication from SNO that they are becoming
  nactive, not ns
• Dmsolar2? 1x10-4eV2 or even lower
• ne appearing in a nm beam made in Los Alamos
• DmLSND2? 2 to 0.1eV2

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What do we ultimately want to know from n
oscillations?

• How many neutrinos are there? Are any sterile?
  Where?
• What is the precise scale of mass splittings?
• What is the mass hierarchy?
• Mixing in atmospheric and solar sectors appears
  maximal is it really maximal, or just close?
• Is Q13 0? Is it l,l2, or l3? Need
  precision!
• Is there CP in the lepton sector?

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Three Generation Neutrino Oscillations
Produce Detect Weak Eigenstate, Detect Mass
Eigenstate
U

• Probability of na to nb
• Oscillation has contributions from every Dm2
• Other ? 3 generation bonus
• CP Violation

Add all 3 Amplitudes and Square
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Parameters of Neutrino Oscillation

• (s13sinQ13, c13cosQ13)
• 3-generation mixing
• Q13,Q32,Q12,d, just like CKM

• Standard Scenario
• Q12, Dm12 from solar n
• Q23, Dm23 from atmospheric n
• Still missing Q13 and d
• CP Violation

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To fully understand the physics behind fermion
mass and mixing

• New Facilities
• Upgraded proton source (1-4MW)
• Very intense n beams
• Ultimately, a n factory
• New Detectors
• Focus on ne appearance and nm disappearance
• If LSND signature is oscillations nt appearance
  gets higher priority
• Of course, were not the only ones excited about
  addressing these issues

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Superbeam Proposals
Name Start Year Proton Power Proton Energy Neutrino Energy Baseline (km)
JHF to SuperK 2008? 0.77MW 50GeV 0.7GeV 350km
JHF to HyperK 2013? 4MW 50GeV 0.7GeV 350km
CERN to UNO ?2011 4MW 2.2GeV 250MeV 130km

• All three use water Cerenkov detectors
• One uses already existing detector
• All three require new beamlines to be built
• Few ? 10-3 background fractions required !
• All have near detectors

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Superbeam Proposals, Continued
m
n
Name Years of running K-ton sin22Q13 Sensitivity(3s) CP Phase d Sensitivity (3s)
JHF to SuperK 5 yrs n 50 0.016 none
JHF to HyperK 2 yrs n 6 yrs n 1000 0.0025 ? 15o
CERN to UNO 2 yrs n, 10 yrs n 400 0.0025 ?40o

• Is there another way to measure these parameters?
• What has not been measured here?

T. Nakaya, JHF
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The Case for a High Energy Superbeam

• The nm to ne measurement is extremely important
  for determining the mixing matrix structure
• At any one baseline the error will be due to a
  combination of systematic and statistical errors
  on background levels
• Two baselines and energies will ensure that
  oscillations are in fact occurring and not
  something completely different.
• The mass hierarchy may be different from what
  people naively expect!
• If so the matter effects will enhance the
  antineutrino s, not the neutrino s
• You would want the longer baseline to see it for
  the first time!
• If JHF-Kamiokande sees CP violation, many years
  from now, they will still have an 8o uncertainty
  due to matter effects

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Capabilities of High Energy Superbeams

• Assumptions
• Narrow Band Beam tuned at oscillation peak
• 70kTon fiducial volume detector, 50 effic.
• 2 years n, 6-8 years n (to get equal statistics)
• Background fraction of 0.4
• 4 x (1/5 NUMI ME) Flux x (730km2/ L2)
• Dm232 3.5x10-3 eV2 Dm232 10-4 eV2

Baseline (km) E n (GeV) sin2Q13 Reach(3s) n n sin2Q13 Reach(3s) n n Sign (Dm232) d (o) (3s) sin2Q131
350 1 .0013 .0016 - 20
730 2.1 .0017 .0026 - 24
1290 3.7 .0020 .0052 .04 32
1770 5 .0022 .0092 .02 40
2900 8.2 .0025 .037 .01 76
Calculated during SNOWMASS Barger, Marfatia,
Whisnant
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Superbeam detector optionswith broad physics
reach
Water Cerenkov ne appearance proven Below
1GeV! Questions What about higher energies? Can
we get to 10-3 background?
Liquid Argon TPC Superb imaging
quality Questions Can such a large volume Of
cryogenic material be put underground? Is 10-3
background achievable in data? (MC looks
promising)
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Electron Candidate in Liquid Argon TPC

• 300 tons operating now
• Need to see how large a single volume can be made

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Neutrino Factory Capability

• Beam comes from
• Above 10 GeV muon storage rings, get much more nm
  out per proton power
• Backgrounds for ne? nm at the 10-4 level or
  better with old detector technology
• The ONLY way we know to get a ne beam!
• Very well-known fluxes makes for very high
  precision on mixing angles and mass splittings

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From Superbeam to Neutrino Factory
DetectorCharge ID
In a granular detector (?x 100 ?m) B1T, One
can start to imagine discriminating e from
e- BUTonly those that shower lateMuons in this
field should work well

• tt

M. Campanelli, ICARUS detector MC
UNO Design
Primary goal in neutrino factory muon charge
identification
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Neutrino Factory Reach
Factor of 10 better Than JHF upgrade! If LMA and
Q13 small, Might even see signs of solar mass
scale! Larger parameter space accessible for CP
studies (hep-ph/010352)
If LSND confirmed Look for nt appearance at
shorter BaselinesCP studies galore! (hep-ph/01035
2)
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Path to a muon storage ring neutrino experiment
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Theres more to life than oscillations

• We need diversity If we look for new physics
  under only one lamppost we are sure to miss
  something!
• We need more lampposts!
• In particular, we may be getting hints of new
  physics in the muon sector
• We cannot let this hint go untested!
• Steps towards a neutrino factory can also provide
  needed lampposts.

E821, Brookhaven, 3.2B ecant be wrong
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New Lampposts

• On the way to a high energy muon collider, we
  will learn to build
• Neutrino superbeam from high intensity (1- 4
  MW) proton driver
• Low-emittance, low energy spread muon beam at 200
  MeV
• ?3 GeV muon beam
• 20-50 GeV muon storage ring
• Muon Collider operating as a Higgs Factory

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Muons do more than decay Charged Lepton Flavor
Physics
m to e conversion SUSY predicts 10-15 level In
scenario where ns oscillate Two order of
magnitude improvements possible
Now Proton driver 200 MeV ? 3GeV
? 20 -50GeV ? storage ring
m EDM Violates P and T reversal invariance! A
measurement indicates new physics Could improve
by 4 orders of magnitude!
(g-2)m 2.6s discrepancy now best probe of tan b
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m to e conversion at BNL-AGS
Looks like the front of a Neutrino factory
5x1011 m/spill Start 2006 Goal B(m Al ? e Al)
10-17
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Neutrinos do more than oscillate Istandard and
exotic processes
Structure functions Scattering off protons
deuterons yields quark-by-quark description of
nucleon Detectors low mass, good PID, tracking,
energy, charge measurements (liquid
TPCs?) Polarized targets?
Now Proton driver 200 MeV ? 20 GeV ?
storage ring 50 GeV ? storage ring Muon
collider
Neutrino magnetic moment (conventional) High
statistics at superbeams enable
order-of-magnitude improvements (non-conventio
nal) resonant cavities? phase rotation?
Heavy flavor production Charm and bottom via
CC/NC c b content of nucleon get CKM matrix
elements Detectors need high precision tracking
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Neutrinos do more than oscillate IIlepton
number violation

• PROCESSES nme- ?m-ne (Em gt 10.7
  GeV)
• nee-? m- nm (Em gt 10.7
  GeV)
• m?e nm ne
  (Em lt 10.7 GeV)
• Each violates lepton family number (?L2)
• Consequence of left-right theories and dileptons
• Signature of a wrong-sign (µ-) in a µ beam.
• Low energy stage will improve limits by 1-2
  orders of magnitude.
• High energy limit limited only by detector
  efficiency. Improve limits by 2-3 orders of
  magnitude.
• Requires good charge and particle identification.

Detector 1km from source, 100 efficiency, µ/p
decay rate taken into account
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Physics at a Muon Collider / Higgs Factory

• Can measure Higgs boson mass to 100 keV
• s-channel Higgs production cross section much
  higher with m
• Can measure Higgs width to 1 MeV
• Hints in current scenario
• 115 GeV Higgs with SM couplings?
• (g-2)m discrepancy of 2.6s
• b?sg
• For large values of tan b, there is a range of
  heavy Higgs boson masses for which discovery is
  not possible at LHC or ee- LC
• Higgs Factory muon collider is a step towards the
  high energy muon collider!

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E1 working group position paper

• The recent evidence for neutrino oscillations is
  a profound discovery. The US should strengthen
  its lepton flavor research program by expediting
  construction of a high-intensity conventional
  neutrino beam ("superbeam") fed by a 1 - 4 MW
  proton source.
• A superbeam will probe the neutrino mixing angles
  and mass hierarchy, and may discover leptonic CP
  violation. The full program will require
  neutrino beams at a number of energies, and
  massive detectors at a number of baselines.
  These facilities will also support a rich program
  of other important physics, including proton
  decay, particle astrophysics, and charged lepton
  CP- and flavor- violating processes.
• The ultimate laboratory for neutrino oscillation
  measurements is a neutrino factory, for which the
  superbeam facility serves as a strong foundation.
  The development of the additional needed
  technology for neutrino factories and muon
  colliders requires a ongoing vigorous RD effort
  in which the US should be a leading partner.

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Conclusions

• Were in the middle of a fundamental discovery
  this IS the frontier!
• We need new beamlines and new detectors to
  explore this new world
• Proton drivers (1-4MW)
• Superbeam
• Large underground detector
• Neutrino Detectors can bring diverse physics
• Proton decay
• Atmospheric solar neutrino studies
• Neutrino Beamlines can also bring diverse
  physics
• Precision muon physics (edm, g-2, etc)
• Neutrino non-oscillation physics
• The ultimate laboratory for oscillation
  measurements is a neutrino factorywe need to
  pursue RD NOW to make it happen