High Pt B-Tag Outline

• Algorithms
• Immediate
• On a short time scale, deliver 2-D only SECVTX & JetProb tags
• Conservative
• Use in analyses which might be systematics dominated, eg Top
• Decay length method with straight cuts
• Lxy for each track with respect to primary vertex with optimal addition of Lsz
• Segregate into categories based on quality of lifetime info and combine with CL technique (see Tracking).  Similar to jet probablility.
• Secondary vertex tag
• Compare SECVTX-like tags (in 3-D) for eff vs purity
• Aggressive
• Use in analyses which aren't systematics dominated, eg Higgs
• Neural network or vector state machine:
• Best input will be lifetime discriminant of conservative method
• Secondary vertex info: number, mass, significance
• Inclusive lepton info: P, Pt
• Jet shape: boost, width
• Auxiliary variables: eg, theta to downweight lifetime info in forward region
• Realistic MC
• Need broad based attack on a realistic description of Si detector
• Charge deposition model
• Noise
• Fake hits
• Smearing of real hits
• As a function of run number
• Dead regions
• Bad strips
• Ladders which aren't turned on
• Ladders which are turned on but not biased
• Readout errors
• All as a function of run number
• Misalignments
• Gain variations
• Final fudge to hit resolution and eff
• Silicon
• Need results from SiStudies Group
• Intrinsic + reconstruction hit efficiency
• Optimal weights for SiHit in track fit
• Use standalone tracking
• vs Incidence angle
• vs Cluster width
• Use log-like fit for unit gaussians for imact parameter significance of known zero-lifetime particles with high Pt (>10GeV) tracks
• Tracking
• Standardized track selection
• Need alignment
• Need COT calibration/efficiency
• Use Kalman filter fit for material and transport of error matrix
• Make track categories to rank lifetime info
• Categorize based on impact parameter error and fakes
• Fit resolution function for each category separately
• COT only (2D)
• COT + r-phi (2D)
• COT + s-z (3D)
• Subcategories based on hit patterns
•  Use COT + r-phi (2D) as fall back if compatibility test fails
• Primary Vertex
• Beam line per run
• Nevent vertexes
• Event vertexes
• Use as origin and reference point for tracks
• Triggers
• Need high Pt lifetime triggers.
• Mostly get from physics groups, but we will be probably be the first customers
• A/H -> bb
• bbqq
• bbtautau
• Top
• Z -> bb
• Charm--low pt but large signal
• Others...