Physics working group summary

1
Physics working group summary

• 2nd ISS MeetingKEK, Tsukuba, JapanJanuary
  23-25, 2006
• Walter Winter
• Institute for Advanced Study, Princeton
• For the ISS physics working group

2
Contents

• Introduction
• Meeting summary
• Theory ( and muon physics)
• Phenomenology Non-accelerator measurements and
  new physics
• Physics with a superbeam, beta beam, neutrino
  factory
• Towards the final productPerformance indicators
  and presentation of results?
• Open questions, next steps
• Summary

3
Three-flavor oscillations Requirements
AtmosphericoscillationAmplitude
q23Frequency Dm312
SolaroscillationAmplitude q12Frequency
Dm212
Sub-leading effect dCP
Coupling strength q13
Key to subleadingeffects (CP violation, mass
hierarchy)

• Neutrino oscillation parameters (1s)Dm212 8.2
  10-5 eV2 - 5sin22q12 0.83 - 5Dm312
  (2 2.5) 10-3 eV2sin22q23 1 - 7sin22q13 0.14dCP ?Mass hierarchy?

(see e.g. Bahcall et al, hep-ph/0406294
Super-K, hep-ex/0501064 CHOOZsolar papers)
Superbeam/n-factory/Beta Beam
4
Theory(plus some muon physics)

• Why are the parameters, which we want to study,
  interesting at all?

(more specific versions of big questions)
(Murayama)
5
Flavor symmetry?
(Murayama)

• Same gauge quantum numbers, but mass hierarchy
  and small mixings unnatural (for quarks,
  charged leptons)
• Hidden quantum number?
• Same for neutrino generations, different for
  charged leptons, quarks?
• Break flavor symmetry by small VEV
• Hierachies, e.g., mumcmt ratio Atmospheric
  mixing maximaltwo large mixing angles
• How big quantitatively? From anarchy q13 not too
  small?

SymmetryFlavor symmetry
Emmy Noether
Conserved quantityHidden quantum number
6
Quark-Lepton complementarity?
(Minakata)

• Understand phenomenological relationships between
  quarks and leptons at deeper level
• Example
• Deeper underlying reason or accidental?
• Note CKM/MNSmatrix is compositedof two parts
• Implement QLC?
• Important in future
• parameter precision measurements!

7
Massive neutrinos in cosmology
(Fukugita)

• Two applications Leptogenesis and mass bounds
• Evolution of large scale structure well
  understood massive neutrinos damp fluctuations
  on horizon scale power spectrum!
• Bounds from different combinations of CMB,
  galaxy clustering, cluster abundance, grav.
  Lensing, Lyman a
• Limits 2 eV (CMB alone, robust)0.42 eV (use of
  Lyman a) but systematics issue?
• Future e.g. large cluster surveys ( 100,000)
  0.03 eV!

8
Flavor physics to establish SUSY?
(Hisano)

• Probe origin of SUSY breaking terms and models
  beyond MSSM from studies of flavor and CP
  violation
• Charged LFV (e.g. m - e g) neutrino
  oscillations provide independent information on
  see-sawlarge mixing angles might enhance
  charged LFVespecially q13 measurement would
  allow predictions of charged LFV
• Good example for accumulating complementary hints
  from different experiments to obtain clearer
  picture of physics

9
(Towards) search for charged lepton mixing at
NuFact
(Kuno)
Current proton drivers 108 muons/s(MEG)

• Charged lepton mixing from manydifferent models
• Many diff. Processes, e.g. m - e gSome
  processes detector limited, others beam limited
• Polarized muons useful to reduce backgrounds and
  discriminate modelsproduce e.g. by pion decay at
  rest change spin by crossing field
• Many beam requirements intensity, pulsed or
  continuous beam (dep. on process), low pion
  contamination, narrow energy spread

4 MW PD 1011-12 muons/s(PRISM)
NF Frontend 1014 muons/s
10
LFV in DIS processes
(Kanemura)

• Motivation E. g. Sleptonmixing (SUSY)
  introduces LFV at one loop
• t-associated LFVinteresting for Higgs-boson
  mediated processes
• Use DIS process e.g. m N - t X at neutrino
  factoryO(102) events for 50 GeVAlso possible
  neutrino beam?
• Cross section increases with energy!Therefore
  argument for as large Em as possible
• Problem Misidentification of events/Backgrounds
  MC in progress

11
Phenomenology ( some Theory) of neutrino
oscillations

• Non-accelerator neutrino property measurements
• Non-standard physicsIs there anything else
  beyond three-flavor oscillations?What possible
  mechanisms?How does one test those?

12
Prospects on n properties from non-accelerator
sources
(Choubey)

• Dm212 from KamLANDbut wrong baseline for
  q12New reactor experiment?
• Gadolinium-loaded SK for solar parameters?
• Atmospheric parametersLarge magn. iron
  detector?Precision comparable to LBL Also
  Deviations from maximal mixing, octant degeneracy

13
Unitarity triangles for lepton sector
(Xing)

• Similar to quark sector Use unitarity triangles
• In see-saw mechanism 6x6-Matrix unitaryin all
  realistic scenarios active mixing unitary
• Matter effects change unitarity triangles
• Example Higher Emakes sides comparable
• Easier to calculate area
• Easier to establish CP viol.

14
Status of 32 scheme
(Sorel)

• Can accommodate all data
• Implies Too low BG forsuperbeams, wrong near
  detector non-osc. assumption
• Eventually checked by MiniBOONE !?
• If confirmed Some new interesting physics Two
  new very similar osc. Frequencies introduced CP
  violation by different phases?Then probably new
  SBL experiment needed

15
Lepton flavor violation?
(Sato)

• May appear in production, propagation, or
  detection
• Neutrinos propagate off-shell
• Interference effects if same in/out states
• Strong correlations between osc. and new physics
  parameters
• Different for different types of exp
• Models shown MSSM penguins

Describe produced state by flavor mixture
Describe detected state by flavor mixture
(simplified)
Shift of matter effect
16
Physics with a superbeam, beta beam,neutrino
factory
17
T2KK
(Kajita)

• Idea Double Chooz of superbeams?
• In addition StrongerCP phase dependence
  matter effectsat longer baseline
• 10 systematics hardlyproblem anymore
• Substantially improved mass hierarchy reach

18
Facilities using a Water Cherenkov detector
(Couce)

• Principle advantage of betabeam No intrinsic
  beam BG
• New efficiency andBG matrices for migration
• High gamma beta beambest alternative (even low
  flux)

Two differentoptions!
19
Better neutrino factory detector?
(Winter)

• q13 sensitivityBetter detector threshold makes
  L2000-3000 km very efficient q13-baseline for
  exclusion limit
• Mass hier., CP violationAll of the following
  help
• Better threshold (especially)
• Better energy resolution
• Smaller matter density uncertainty (for large q13)

20
Towards the final productPerformance indicators
and presentation of results?
21
Performance indicators

• Many, many in circulation
• Need to be identical to compare results
• Matter of
• Definition
• Tested hypothesis
• Purpose
• Taste
• Computation power

22
Example q13 performance indicators

• q13 exclusion limit (sensitivity limit)
• Describes the new q13 limit for the hyopthesis
  of no signal (q130)
• Correspond to new limit after the experiment has
  been (unsuccessfully) performed
• q13 discovery reach
• Describes if q130 can be excluded for the
  hypothesis of a certain set of parameters
  (q130)

CP fraction plots often used for discovery
potentials!
23
Example dCP-performance indicators

• Examples
• Allowed region in d-q13-planeIdentify how much
  parameter space remains for specific hypotheses
  of true values
• Sensitivity to max. CP violation p/2 or 3p/2Can
  CP violation be detected for the hypothesis of
  max. CP violation?
• Sensitivity to any CP violationFor what
  fraction of CP violating values can CP violation
  be detected? (CP fraction plots)!
• Precision of d ?How precisely can one measure d?
  (only defined in the high precision limit, since
  d cyclic also not Gaussian!)
• CP coverageHow precisely can one measure d or
  what fraction of the parameter space can be
  excluded?
• Which one(s) useful for ISS study?

True values Few examples
Purpose Looks like result
Level of condensation, computation time
Purpose Risk minimization
True values Complete relevant space
24
Towards the presentation of resultsBuild strong
physics case!

• Main objectives?
• Find q13
• Establish mass hierarchy
• Search for leptonic CP violation
• Important physics limits
• q13 large?Neutrino factory physics case?Or
  vice verse Only if q13 small?Better detector
  key component?
• Physics for q13 zero?Such as by some symmetry
  May be important for fundingagencies!E. g.
  mass hierarchy, MSW effect

Theory neededWhy are these parametersinterestin
g at all?
(Fig. from Huber, Lindner, Winter,
hep-ph/0412199)
25
More physics can be done!

• Include other possible physicsqualitatively or
  quantitatively? How?
• Examples
• Measure q13 precisely as soon as found
• Measure dCP precisely as soon as found
• Measure leading atmospheric parameters
• Deviations from maximal atmospheric mixing
• Resolution of octant degeneracy
• Test unitarity
• New physics ad-mixtures?
• MSW effect sensitivity
• Matter density measurements?

Certainly goodtheoretical motivation,e.g.,
quark-lepton-complementarity, massmodels etc.
26
Example Optimization for large q13

• Mass hierarchy no problem for L 1000 km
• CP fraction for CP violation (3s)StandardOp
  timal appearanceL1000 km/Em20 GeVpossible
  alternative?

Preliminary
(Huber, Lindner, Rolinec, Winter, to appear)
27
Example New physics tests

• How can this be done by simple experimental
  strategies?
• Theory/Phenomenology Link specific models (e.g.
  LFV) with general tests?
• Or Just wait until some inconsistency
  discovered?
• Examples
• nt detection PeePemPet 1? Requires action!
  (Wait and see does not work here )
• Neutral currents (hard, but maybe competitive to
  1. ?)
• Spectral signature from effects on probability
  level (decay, )Advantage Characteristic
  depletion/enhancement in certain regions
  ofspectrum, oscillation nodes not shifted
• More complicated Hamiltonian-level effects (LFV
  etc.)Problem Shifts oscillation nodes,
  confusion with standard parameters
• Note At least 1. and 2. sufficient but not
  necessary for new physics!

See many talks inthis workshop forspecific
possible effects!E.g. Hisano, Kanemura, Sato,
Sorel, Xing
28
Some biased conceptualities

• How to present multiple options, such as for
  detector etc?
• Avoid too many options mixed up (confusing)
• Discuss different options in one section
  andchoose one representative for main lineof
  argumentation?
• Need that representative asap if September
  goal!!!
• Problem Computation time for more complex
  calculations GLoBES on parallel cluster!So far
  used mainly opportunistic systems
• At the end Very small number of meaningful key
  figures required

29
Open questions

• Physics Detector
• Physics Accelerator
• Detector (Physics) Accelerator

30
Open questions Physics-Detector

• Ken Long close loopNeed now best possible
  detector concept (such as in glb-files) with 1.
  Better low energy efficiences2. Better energy
  resolution?
• Can be either one detector or hybrid technology
  (same site)
• Better detector key component in large q13
  discussion!?
• In addition ne detection, silver channel
  concepts Relevance for physics, optimization,
  baselines

31
Open questions Physics-Accelerator

• Physics What muon energy really required?
• Acc. How much would that reduce the effort?
• Example 40 GeV for q13, dCP, mass hier.
• Physics How large can flux uncertainty be?
  (Scott Berg)

32
Storage ringpossible NF program?

• t0 yr Start with one baseline, two polarities,
  golden channel, L3,000 km Em 20 GeV,
  mD50kt, 2 MW proton driver?
• t3 yr First data analysisProblem not in
  fortunate region in param. spaceDecision Go to
  magic baseline silver channel after five
  more years of data taking
• t5 yr Upgrade, still at L3,000 km Em 40
  GeV, mD100kt, 4 MW proton driver
• t8 yr Stop data taking connect new storage
  ring
• t10 yr Start at magic baselinesilver channel
  (new baseline) with one polarity (neutrino
  appearance only)
• t13 yr Data analysis Signal! Start precision
  measurement
• t15 yr Decide to change polarity
• t20 yr End of program

silver
Flexible storage ring concept? Physics How many
baselines?
MB
33
Open questions Detector-Accelerator(maybe not
our business )

• 3s sensitivity to sin22q13
• Optimization Better detector versus higher muon
  energy?

Better Eres
Better threshold
Better Eresthresh.
Preliminary
(Huber, Lindner, Rolinec, Winter, to appear)
34
Next steps Goals for Boston

• Conceptual cases? Link to theory?Examples
• Large q13 sin22q13 0.01(Physics case for
  NuFact at all? vs. Superbeams?)
• Small q13 10-4 golden age?)
• Zero q13 sin22q13 done? What does that mean?)
• How to deal with a positive MiniBOONE signal?
  Disaster or golden age of neutrino
  physics?Last-minute changes or matter of
  argumentation?How to conceptualize new physics
  tests and post-MiniBOONE physics?
• How many baselines needed?
• Channel requirements, optimization,

35
Summary

• Theory/phenomenology very rich information
  collected from many different sources
• Next steps How to conceptualize/order
  that?General approaches to new physics tests?
• Experiment simulations and muons
• Partly work in progress (superbeams, beta beams,
  etc.)
• But At this put input from detector
  (accelerator) WG required (best to come up with)
• Some open questions (such as channel
  requirements)
• Next steps Concept! Work on physics cases ...
  Think about final product