Summary of the Signatures IV Group

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Summary of the Signatures IV Group
Momentum Reconstruction, V0 Finding, and Charged
Particle ID
ALCPG07 FNAL Oct 26 2007 Bruce Schumm,
UCSC/SCIPP
Apologies to 4th Concept (Im not yet familiar
enough to be confident in criticism)
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Ideal A balancing between theoretical impact and
experimental capability Reality Identification
of a number of issues that should probably
receive more attention Usual candidates SUSY,
SM Higgs, but with some new or re-calibrated
emphasis
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SUSY in Perspective (Tom Rizzo) Can
the ILC at 500 GeV distinguish all of the MSSM
models (i.e., parameter space points) that
were found to give degenerate signatures
at the LHC ?? Can the SUSY particles in all
these models be observed at ILC?
Along the way to answering these questions we
needed to perform a general study of signals
backgrounds for hundreds of SUSY models
providing a unique opportunity to
examine, e.g., signatures, cuts, detector and
simulation properties our basic
assumptions/prejudices about SUSY analyses
at the ILC. These hundreds of models
include some interesting signatures, some of
which challenge one or both of the detector
concepts
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Anomaly-Mediated Supersymmetry Breaking
and how it dies.
How long it (??) lives
Chargino (??) tends to be nearly degenerate with
neutralino (?0) ? For ?M lt m?, phase-space
suppression leads to nearly-stable particles
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Anomaly-Mediated Supersymmetry Breaking II
Rizzo et al. have developed a workable selection
for Ecm 500 GeV
Faster (lighter) ruled out by direct searches
(LEP)
The velocity criterion ?p/E lt 0.93 is
interesting
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Long-Lived Heavy Charged Particle
Region of interest
But LHC will probably see or rule out
lighter Probably not a motivation for dedicated
PID?
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Or ?M ? m? Soft Isolated Tracks
Signature can be extremely challenging Two
charged tracks with p?? 200 MeV Two-photon
backgrounds will be challenging (identify
deflected beam electron with angles Theta
p??/Ebeam or less if deflected electron detected
as a charged track. (other electron Can this be
done even in limit of perfect trackinf
? ? ? ?0 ? cosmologically preferred
(co-annihilation)
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Gauge-Mediated Supersymmetry Breaking
Scenarios with in-flight decay are motivated by
cosmological constraints
This will challenge SiD Gaseous trackers? (For
TPC, non-pointing ? out-of-time)
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Light Selectrons
Selectrons vs. cos(?)
Opening of t-channel pitches majority of signal
forward. But also
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Spectrum is weighted towards higher energy at
high cos(?), increasing stats/ at critical
upper endpoint
Electron Energy Specturn
0
150
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For light SPS1a-like scenario, majority of
slepton mass information would be in forward
direction This would challenge any
solenoidal-geometry design
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Other Interesting Forward Physics Ee -gt
ff Triple gauge boson coupling
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Precision Momentum Measurement H? ?? (Yang,
Riles, U. Michigan)
Higgs BFs (vs MH)
Since light Higgs is narrow, spec- ulate that M??
resolution is limited by tracker resolution
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H? ?? Significance vs. Tracker resolution
Rescaling factor rel- ative to SiDMar01 ?(1/p?)
a ? b/p? a 2 x 10-5 b 7 x
10-4 Sensitivity improves well beyond 2 x 10-5
Best shot at 2nd gen. fermion? (H. Logan)
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What About Dedicated Charged Particle ID?

• Can be useful in flavor charge separation
• H ? bb vs. H ? cc
• Forward-backward asymmetries in
• ee- ? Z? ? ff
• ?,K indicative of heavy flavor cascade, and tag
  charge

Probably best to study via vertex recon-struction
Neural Net no group has yet taken this on.
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Summary
Doing everything we want to will be
challenging. Blah blah cosmologically
motivated hard
Good thinking from Battaglia et al.,
hep-ex/0603010. Experimenters Focus largely on
these for LOI, Theorists/Experimental Explore
other ideas for post-LOI evaluation
Artwork courtesy J. Pollock
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RANDOM (THOROUGHLY) BACKUP SLIDEES
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SPS 1 Spectroscopy At Ecm 1Tev, selectrons
and neutralino are light.
selectrons

• Beam/Brehm
• vsmin1
• vsmax1000
• .29
• sz .11 (mm)

LSP
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Now, include the full region (cos? lt 0.994)
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SCHUMMS GUIDE to squeezing blood from
stone