class AtlSgTop_tChannelFinder: public AtlKinFitterTool

 Single top t-channel event finder

 Helper class for conducting a kinematic fit and/or cut-based analysis
 of the t-channel of single-top.

 Used by AtlSelector.


 The Finder is looking for events with at least two jets and a W (in channels
 W->e nu, W->mu nu). One of the jet (the b-jet) is combined with the W to
 reconstruct a top quark. The finder selects the combination with the smallest
 chi^2 of the KinFitter output to be the reconstructed event.


 Use this tool by adding it to the task class of your analysis job
 like this:

  //************************************************************

  class YourTask : public AtlAppAnalysisTask {
  .
  .
  .
  }

  void YourTask::InitSelector() {
  
  // Initialise the analysis selector of your analysis
  
  fSelector = new YourAnalysis(fOutputFileName->Data());

  // ===============================================================================
  // Definition of selection cuts for your (dummy or alternative cut-based) analysis
  // ===============================================================================
  SetCut(...)
  .
  .
  .
  
  // Add kinematic fitting procedure
  
  AtlSgTop_tChannelFinder *kinfit =
  new AtlSgTop_tChannelFinder("sgtop_finder_kinfitter",
 	    "Single-Top t-Channel Reconstruction by KinFitter");
  SetToolCut("sgtop_finder_kinfitter", "fMode", "AtlKinFitterTool::kKinFit");
  SetToolCut("sgtop_finder_kinfitter", "fModeMass", "AtlSgTop_tChannelFinder::kGauss");
  SetToolCut("sgtop_finder_kinfitter", "fBJetTagger",    "AtlBTag::kBaseline");
  SetToolCut("sgtop_finder_kinfitter", "fBJetWeightMin", "4.0");
  .
  .
  .
  fSelector->AddTool(kinfit);

  //************************************************************

 When included in the analysis task this class appends an additional
 directory structure to the output file in which the output histograms are
 stored.

 If the finder should be run in KinFitter mode, set fMode = kKinFit,
 if the finder should be run in cut-based mode, set fMode = kCutBased,
 if the finder should be run in both modes, set fMode = kAll.

 fChi2ProbMin provides the P(chi2) cut on the main fit.
 fVetoWhadProbMin gives the P(chi2) cut on the veto fit of an additional
 hadronically decaying W.

 If the usage of MissingEtRefFinal is desired, set fUseMETRefFinal = kTRUE via
 SetToolCut().

 If truth-matching is desired, set fTruthMatch = kTRUE via SetToolCut().

 If informational and/or debug output is desired, set the verbosity level
 via tool->SetVerbosityLevel(Int_t VerbosityLevel) in your task file:

 -> If only informational output on the reconstructed top-quark and hadronic
    W boson is desired, set VerbosityLevel = 1.
 -> If debug output is desired, set VerbosityLevel = 2. This will print the
    fit objects and their respective covariance matrices, preceeding and
    succeeding the fit (main fit and Whad veto fit).

 If even more detailed debug output is needed, set the verbosity level of the
 KinFitter object by hand in this file!

 Author: Patrick Rieck <mailto:rieck@physik.hu-berlin.de>
 Copyright: 2009 (C) Patrick Rieck