Do a constrained kinematic fitting for a $t\bar{t}\to\ell + \rm{jets}$ event. More...

#include <Constrained_Top.h>

Public Member Functions
double	constrain (Lepjets_Event &ev, double &mt, double &sigmt, Column_Vector &pullx, Column_Vector &pully)
	Do a constrained fit of $t\bar{t}\to\ell + \rm{jets}$ events. Returns the top mass and its error in mt and sigmt, and the pull quantities in pullx and pully. Returns the $\chi^{2}$ , this will be negative if the fit failed to converge.
	Constrained_Top (const Constrained_Top_Args &args, double lepw_mass, double hadw_mass, double top_mass)
	Constructor, create an instance of the Constrained_Top object from the arguments object and the mass constraints.
Private Attributes
const Constrained_Top_Args	_args
Fourvec_Constrainer	_constrainer
Friends
std::ostream &	operator<< (std::ostream &s, const Constrained_Top &ct)
	Output stream operator, print the content of this Constrained_Top object to an output stream.

Detailed Description

Do a constrained kinematic fitting for a $t\bar{t}\to\ell + \rm{jets}$ event.

Definition at line 129 of file Constrained_Top.h.

Constructor & Destructor Documentation

hitfit::Constrained_Top::Constrained_Top	(	const Constrained_Top_Args &	args,
		double	lepw_mass,
		double	hadw_mass,
		double	top_mass
	)

Constructor, create an instance of the Constrained_Top object from the arguments object and the mass constraints.

Parameters:

args	Argument for this instance of Constrained_Top object.
lepw_mass	The mass to which the leptonic W should be constrained. If this parameter is set to 0, the constraint is skied.
hadw_mass	The mass to which the hadronic W should be constrained. If this parameter is set to 0, the constraint is skied.
top_mass	The mass to which the top quarks should be constrained. If this parameter is set to 0, the constraints is skied.

Definition at line 107 of file Constrained_Top.cc.

References _constrainer, hitfit::Fourvec_Constrainer::add_constraint(), hitfit::Constrained_Top_Args::equal_side(), hitfit::hadb_label, hitfit::hadw1_label, hitfit::hadw2_label, hitfit::lepb_label, hitfit::lepton_label, hitfit::Fourvec_Constrainer::mass_constraint(), and hitfit::nu_label.

  : _args (args),
    _constrainer (args.fourvec_constrainer_args())
{
  char buf[256];
  if (lepw_mass > 0) {
    sprintf (buf, "(%d %d) = %f", nu_label, lepton_label, lepw_mass);
    _constrainer.add_constraint (buf);
  }

  if (hadw_mass > 0) {
    sprintf (buf, "(%d %d) = %f", hadw1_label, hadw2_label, hadw_mass);
    _constrainer.add_constraint (buf);
  }

  if (args.equal_side()) {
      sprintf (buf, "(%d %d %d) = (%d %d %d)",
               nu_label, lepton_label, lepb_label,
               hadw1_label, hadw2_label, hadb_label);
      _constrainer.add_constraint (buf);
  }

  if (top_mass > 0) {
    sprintf (buf, "(%d %d %d) = %f",
             hadw1_label, hadw2_label, hadb_label, top_mass);
    _constrainer.add_constraint (buf);
  }
  else {
    sprintf (buf, "(%d %d %d) = 0", hadw1_label, hadw2_label, hadb_label);
    _constrainer.mass_constraint (buf);
  }
}

Member Function Documentation

double hitfit::Constrained_Top::constrain	(	Lepjets_Event &	ev,
		double &	mt,
		double &	sigmt,
		Column_Vector &	pullx,
		Column_Vector &	pully
	)

Do a constrained fit of $t\bar{t}\to\ell + \rm{jets}$ events. Returns the top mass and its error in mt and sigmt, and the pull quantities in pullx and pully. Returns the $\chi^{2}$ , this will be negative if the fit failed to converge.

Parameters:

ev	The event to be fitted (input), and the event after fitting (output).
mt	The fitted top mass.
sigmt	The uncertainty on the fitted top mass.
pullx	Pull quantities for the well-measured variables.
pully	Pull quantities for the poorly-measured variables.

Input:

Lepjets_Event ev.

Output:

Lepjets_Event ev.
double mt.
double sigmt.
Column_Vector pullx.
Column_Vector pully.

Return:: The $\chi^{2}$ of the fit. Return a negative value if the fit didn't converge.

Definition at line 291 of file Constrained_Top.cc.

References _args, _constrainer, hitfit::Constrained_Top_Args::bmass(), and hitfit::Fourvec_Constrainer::constrain().

Referenced by hitfit::Top_Fit::fit_one_perm().

{
  Fourvec_Event fe;
  do_import (ev, _args.bmass (), fe);
  double chisq = _constrainer.constrain (fe, mt, sigmt, pullx, pully);
  do_export (fe, ev);

  return chisq;
}