Constrained_Top.h

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//
// $Id: Constrained_Top.h,v 1.1 2011/05/26 09:46:53 mseidel Exp $
//
// File: hitfit/Constrained_Top.h
// Purpose: Do kinematic fitting for a ttbar -> ljets event.
// Created: Jul, 2000, sss, based on run 1 mass analysis code.
//
// CMSSW File      : interface/Constrained_Top.h
// Original Author : Scott Stuart Snyder <snyder@bnl.gov> for D0
// Imported to CMSSW by Haryo Sumowidagdo <Suharyo.Sumowidagdo@cern.ch>


#ifndef HITFIT_CONSTRAINED_TOP_H
#define HITFIT_CONSTRAINED_TOP_H


#include "TopQuarkAnalysis/TopHitFit/interface/Fourvec_Constrainer.h"
#include "TopQuarkAnalysis/TopHitFit/interface/matutil.h"
#include <iosfwd>


namespace hitfit {


class Defaults;
class Lepjets_Event;

class Constrained_Top_Args
//
// Purpose: Hold on to parameters for the Constrained_Top class.
//
// Parameters controlling the operation of the fitter:
//   float bmass        - The mass to which b jets should be fixed.
//
{
public:
  // Constructor.  Initialize from a Defaults object.
  Constrained_Top_Args (const Defaults& defs);

  // Retrieve parameter values.
  double bmass () const;

  // Arguments for subobjects.
  const Fourvec_Constrainer_Args& fourvec_constrainer_args () const;

  // Retrieve requirement for equal mass on both sides
  bool equal_side() const;

private:
  // Hold on to parameter values.

  double _bmass;

  Fourvec_Constrainer_Args _fourvec_constrainer_args;

  bool _equal_side;

};


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


class Constrained_Top
//
// Purpose: Do kinematic fitting for a ttbar -> ljets event.
//
{
public:
  // Constructor.
  // LEPW_MASS, HADW_MASS, and TOP_MASS are the masses to which
  // those objects should be constrained.  To remove a constraint,
  // set the mass to 0.
  Constrained_Top (const Constrained_Top_Args& args,
                   double lepw_mass,
                   double hadw_mass,
                   double top_mass);

  // Do a constrained fit.
  double constrain (Lepjets_Event& ev,
                    double& mt,
                    double& sigmt,
                    Column_Vector& pullx,
                    Column_Vector& pully);

  // Dump out our state.
  friend std::ostream& operator<< (std::ostream& s, const Constrained_Top& ct);


private:
  // Parameter settings.
  const Constrained_Top_Args _args;

  // The guy that actually does the work.
  Fourvec_Constrainer _constrainer;
};


} // namespace hitfit


#endif // not HITFIT_CONSTRAINED_TOP_H