Physics withs Taus and Jets

1
Physics withs Taus and Jets
2
Taus in SUSY decay chains
3
Quasi exclusive analysis
4
Tau signatures in SUSY

• Tau signatures are important in much of the
  mSUGRA parameter space, particularly at high tan?
• At some points in the parameter space (e.g.
  funnel) can only observe kinematic endpoints in ?
  invariant mass distributions
• Taus provide independent information even if
  lepton signatures are available
• Tau ID is much harder than electron or muon ID,
  particularly for soft taus (e.g. co-annihilation
  point)
• ? typically achieve ?/jet ? 100 for a tau
  reconstruction efficiency of 50

5
Standard SUSY offline analysis

• Consider the decay chain

Rome.004423.SU3.AOD
6
Standard SUSY offline analysis

• Decay chain involving taus
• Reconstruct only hadronic tau decays.

20K events
Caveat Tau are polarized visible mass depends
on polarization needs tau polarization info for
proper mass estimate
7
Interesting areas

• Tau-Tau invariant mass
• tau polarization p(?)/p(t jet)
• precision on edge position (polarization effects
  experimental effects)
• ? critical for precision on mass determination
  ? constraining model ? estimate neutralino dark
  matter density
• Tau-jet invariant mass
• sfermion-fermion-gaugino interactions conserve
  the chirality of (s)fermions ? charge asymmetry
  in m(jt) distributions from the cascade decay q
  ? q ?2? t t
• ? info about stau mixing

8
Pt of Tau
pT (GeV)
pT (GeV)
9
Interesting areas (2)

• Taus are rather low pT, specially the second one
  in the chain.
• Try mixed chains of hadronic and leptonic tau
  decays mt (had)t (e/µ) First check
  visibility of kinematic structure with Atlfast
• Use Tau1p3P package
• Study trigger efficiency t35ixET45 J70xET70
  others... for benchmark points
• optimize for low pT

10
time profile

• Before start
• develop expertize
• offline tau reconstruction
• tau trigger
• optimize analysis strategy and trigger
• early data try to identify structure
• more statistics constraint models

11
FromJet reconstruction/calibration- QCD
Background to new physics
12
evolving from gammajet

• starting point current work gammajet for
  in-situ jet reconstruction commissioning
• Jet reconstruction calibration/algorithms/effec
  t of Noise,UE,MinBias
• Underlying Event, Jet multiplicity, QCD
  measurement
• 2006 Tesina Sigrid
• Move towards QCD measurement (and search)
• for example di-photon
• N.B similar studies can be done with Zjet