Summary of May Workshop

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Summary of May Workshop
David B. MacFarlane UC San Diego
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May Workshop

• Goal Evaluate physics case for asymmetric-energy
  ee- collider with 1036 luminosity

Working Groups
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Ingredients of a Physics Case

• Level of experimental precision
• Including new analysis techniques
• Expected theoretical precision
• Implications of New Physics
• Mass scale reach no longer relevant measure of
  performance
• Can we distinguish between models, e.g. SUSY
  breaking?
• Measure new flavor violation and CP parameters

Focus on observables where ee- offers unique
opportunities and/or precision
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Context for Super B Factory

• Need to define capability for exploring beyond
  Standard Model physics
• Knowing that the CKM mechanism produces CP
  violation in B decays
• Knowing that such a facility would operate after
  the start of the LHC in an era of direct searches
• Suppose the LHC discovers new physics how would
  a Super B Factory contribute to our
  understanding?
• How unique are these capabilities? What about
  LHCb or BTEV? What about a LC, should one be
  built?
• Suppose the LHC does not discover new physics
  what discovery potential would remain?
• How unique are these capabilities? What about
  LHCb or BTEV?

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New Physics Discovery Potential
LC
Super B Factory
LHC
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New Physics Exploration Potential
Suppose SUSY is seen now measuring properties
LC
Super B Factory
LHC
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WG1 Rare Decays

• Investigating channels of potential interest as
  probe for new physics
• Exclusive and inclusive b sg BFs, direct
  asymmetries, photon helicities
• Exclusive and inclusive b sll- BFs, AT, AL,
  AFB, CP asymmetries
• B decays to states with large missing energy,
  such as B(d,s) tt-, B K()nn , b snn , B
  D()tnt , B XCtnt

dBF(b sg) 2 for 10 ab-1 vs theory error NNLO
5 dACP(b sg) 1 for 10 ab-1
O(30-100) candidates for B K()nn in 10 ab-1
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Fully Reconstructed B Sample
Old idea with new level of sensitivity
Reconstruct B mesons in 1000 modes
S/B0.3
Efficiency 0.4 or 4000 B mesons/fb-1 (charged
and neutral)
Require lepton p gt 1GeV/c
S/B2.5
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B g Knn signal selection
Signal signature is a single kaon and nothing
else recoiling against an opposing reconstructed B
Significant background rejection results from low
signal multiplicity and total calorimeter energy!
S.Robertson
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Sensitivity Guestimates
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Zero-Point of FB Asymmetry
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Projections of Experimental Precision
S.Willocq
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WG2 Error Projections for ACP
1.0
Error on ACP
10-1
10-2
10-2
10-1
1
10
102
Integrated Luminosity
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Intriguing Hint from Penguins?
3.1 sigma below charmonium modes
If central value remains as is, this would become
5 sigma by 2005
Is this the Super B killer app?
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Isospin Analysis for
No Penguin contribution
Gronau-London, 1990
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Toy MC Study
BABAR Long-Range Task Force
Method appears to be well suited to Super B
Factory
Scaled from present efficiencies/backgrounds
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WG3 Sides of the UT
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Improvements in Precision
M.Luke
Ultimate error 5
Optimized mX and q2 cut
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Exclusive Charmless Decays Sensitivity
D.Del Re
Two examples in 500fb-1 using B reconstructed
sample
B?p0ln
B?r0ln
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Excl. Charmless Decays Prospects
Assumes negligible systematic error from FF
and uses rough estimate of exp. syst. error
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WG4 New Physics
Extensions of the SM

• Modify ACP(B0 f KS) through additions to loop
  diagram
• Impact constrained by other b s processes
• EDM, eK, Dmd, Dms, b sg

Y.Okada
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SUSY in Super B Factory Era

• LHC experiments will be a crucial test for
  existence of SUSY (squark/gluino mass reach 2
  TeV for a light Higgs boson)

Mass spectrum from LHC and LC will provide a hint
for a SUSY breaking scenario
G.A.Blair, W.Porod, and P.M. Zerwas
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Role of Flavor Physics

• Determine flavor structure of squark mass
  matrices (new flavor mixing and new CP phases.)
• Quark mass -gt Yukawa coupling
  Squark mass -gt SUSY breaking
  terms
• SUSY breaking terms depend on SUSY breaking
  mechanism and interaction at the GUT/Planck scale

Diagonal term LHC/LC Off diagonal term Flavor
Physics
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Pattern of Deviation from SM Predictions
Unitarity triangle
Rare decay
Y.Okada
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Detector Considerations

• Both Babar and Belle have started to look at
  upgrade paths to make the detectors 1036-capable
• 1036 is quite different from 1035 current
  detectors could be stretched to work at 1035 with
  relatively minor changes, but require a lot of
  changes at 1036
• Main concerns are
• Machine-related backgrounds
• synchrotron radiation
• particle backgrounds, due primarily to continuous
  injection
• Radiation dose
• Physics backgrounds hadronic split-offs, ..
• Main criteria for the design of upgraded
  detectors
• Performance at least as good as current detector
• Can withstand the high background level

Tracking, PID, calorimetry, trigger, computing
F.Forti
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Calorimetry Occupancy

• Both Babar and Belle use CsI(Tl) crystals, which
  have high light yield, but are relatively slow
• Just on the basis of occupancy, the calorimeters
  are not usuable at 1036
• Radiation damage is also important

Nclusters gt 10 MeV
Occupancy
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Ongoing Workshop Goals

• Very large (10-50 ab-1) samples will enable a
  large number of very precise measurements and
  significantly improved sensitivity for rare
  decays
• How precise can the measurements become?
• What does a 1036 detector look like?
• Are there new ways of approaching measurements?
• How precise can the theoretical predictions
  become?
• How unique are the measurements?
• Comparisons with hadron B physics experiments
  (not yet proven, but great promise in some areas)
• How well can we probe for or explore New Physics?
• How much will we learn about the flavor couplings
  of New Physics?

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Did you do your summer homework?
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Model Space to Explore

• SUSY
• MSUGRA
• GMSB
• Effective SUSY (light sthird generation)
• CPV squark mass insertions
• CPV Higgs sector
• CPV general 2 Higgs doublet models
• Extra dimensions
• TeV-1 with split fermions
• Others
• Left-right model
• Little Higgs model
• Topcolor