hitfit::Top_Fit Class Reference

Handle and fit jet permutations of an event. This is the primary interface between user's Lepjets_Event and HitFit kinematic fitting algorithm. More...

#include <Top_Fit.h>

Public Member Functions
const Top_Fit_Args &	args () const
	Return a constant reference to the fit arguments. More...
Fit_Results	fit (const Lepjets_Event &ev)
	Fit all jets permutations in ev. This function returns a Fit_Results object, which is not easy to extract information from. Users are recommended to use the class RunHitFit as interface to fit all permutations of all event. More...
double	fit_one_perm (Lepjets_Event &ev, bool &nuz, double &umwhad, double &utmass, double &mt, double &sigmt, Column_Vector &pullx, Column_Vector &pully)
	Fit for a single jet permutation. More...
	Top_Fit (const Top_Fit_Args &args, double lepw_mass, double hadw_mass, double top_mass)
	Constructor. More...

Private Attributes
const Top_Fit_Args	_args
Constrained_Top	_constrainer
double	_hadw_mass
double	_lepw_mass

Friends
std::ostream &	operator<< (std::ostream &s, const Top_Fit &fitter)
	Output stream operator, print the content of this Top_Fit object to an output stream. More...

Detailed Description

Handle and fit jet permutations of an event. This is the primary interface between user's Lepjets_Event and HitFit kinematic fitting algorithm.

Definition at line 244 of file Top_Fit.h.

Constructor & Destructor Documentation

hitfit::Top_Fit::Top_Fit	(	const Top_Fit_Args &	args,
		double	lepw_mass,
		double	hadw_mass,
		double	top_mass
	)

Constructor.

Parameters

args	The parameter settings.
lepw_mass	The mass to which the leptonic boson should be constrained to. A value of zero means this constraint will be removed.
hadw_mass	The mass to which the hadronic boson should be constrained to. A value of zero means this constraint will be removed.
top_mass	The mass to which the top quark should be constrained to. A value of zero means this constraint will be removed.

Definition at line 368 of file Top_Fit.cc.

  : _args (args),
    _constrainer (args.constrainer_args(),
                  lepw_mass, hadw_mass, top_mass),
    _lepw_mass(lepw_mass),
    _hadw_mass (hadw_mass)
{
}

Member Function Documentation

const Top_Fit_Args & hitfit::Top_Fit::args

(

)

const

Return a constant reference to the fit arguments.

Definition at line 609 of file Top_Fit.cc.

References _args.

Referenced by hitfit::RunHitFit< AElectron, AMuon, AJet, AMet >::FitAllPermutation().

{
    return _args;
}

Fit_Results hitfit::Top_Fit::fit

(

const Lepjets_Event &

ev

)

Fit all jets permutations in ev. This function returns a Fit_Results object, which is not easy to extract information from. Users are recommended to use the class RunHitFit as interface to fit all permutations of all event.

Parameters

ev	Input: The event to fit, Output: the event after the fit.

Definition at line 499 of file Top_Fit.cc.

References _args, gather_cfg::cout, hitfit::Top_Fit_Args::do_higgs_flag(), fit_one_perm(), hitfit::hadb_label, hitfit::hadw1_label, hitfit::higgs_label, i, hitfit::isr_label, hitfit::lepb_label, hitfit::n_lists, hitfit::Lepjets_Event::njets(), hitfit::Top_Fit_Args::nkeep(), hitfit::noperm_list, and hitfit::Top_Fit_Args::print_event_flag().

{
  // Make a new Fit_Results object.
  Fit_Results res (_args.nkeep(), n_lists);

  // Set up the vector of jet types.
  vector<int> jet_types (ev.njets(), isr_label);
  assert (ev.njets() >= 4);
  jet_types[0] = lepb_label;
  jet_types[1] = hadb_label;
  jet_types[2] = hadw1_label;
  jet_types[3] = hadw1_label;

  if (_args.do_higgs_flag() && ev.njets() >= 6) {
    jet_types[4] = higgs_label;
    jet_types[5] = higgs_label;
  }

  // Must be in sorted order.
  stable_sort (jet_types.begin(), jet_types.end());

  do {

    // Loop over the two possible neutrino solution
    for (int nusol = 0 ; nusol != 2 ; nusol++) {

    // Set up the neutrino solution to be used
    bool nuz = bool(nusol);

    // Copy the event.
    Lepjets_Event fev = ev;

    // Install the new jet types.
    set_jet_types (jet_types, fev);

    // Figure out on what lists this permutation should go.
    vector<int> list_flags = classify_jetperm (jet_types, ev);

    // Set up the output variables for fit results.
    double umwhad, utmass, mt, sigmt;
    Column_Vector pullx;
    Column_Vector pully;
    double chisq;

    // Tracing.
    cout << "Top_Fit::fit(): Before fit: (";
    for (vector<int>::size_type i=0; i < jet_types.size(); i++) {
        if (i) cout << " ";
        cout << jet_types[i];
    }
    cout << " nuz = " << nuz ;
    cout << ") " << std::endl;

    // Do the fit.
    chisq = fit_one_perm (fev, nuz, umwhad, utmass, mt, sigmt, pullx, pully);

    // Print the result, if requested.
    if (_args.print_event_flag()) {
        cout << "Top_Fit::fit(): After fit:\n";
        char buf[256];
        sprintf (buf, "chisq: %8.3f  mt: %6.2f pm %5.2f %c\n",
             chisq, mt, sigmt, (list_flags[noperm_list] ? '*' : ' '));
        cout << buf;
    }

    // Add it to the results.
    res.push (chisq, fev, pullx, pully, umwhad, utmass, mt, sigmt, list_flags);

    } // end of for loop over the two neutrino solution

    // Step to the next permutation.
  } while (next_permutation (jet_types.begin(), jet_types.end()));

  return res;
}

double hitfit::Top_Fit::fit_one_perm	(	Lepjets_Event &	ev,
		bool &	nuz,
		double &	umwhad,
		double &	utmass,
		double &	mt,
		double &	sigmt,
		Column_Vector &	pullx,
		Column_Vector &	pully
	)

Fit for a single jet permutation.

Parameters

ev	Input: The event to fit, Output: the event after the fit.
nuz	Input: A flag to indicate which neutrino solution to be used. FALSE means use solution with smaller absolute value. TRUE means use solution with larger absolute value.
umwhad	The mass of hadronic boson before the fit.
utmass	The mass of the top quarks before fitting, averaged from the values of leptonic and hadronic top quark mass.
mt	The mass of the top quark after fitting.
sigmt	The uncertainty of the mass of the top quark after fitting.
pullx	Pull quantities for well-measured variables.
pully	Pull quantities for poorly-measured variables.

Definition at line 393 of file Top_Fit.cc.

References _args, _constrainer, _hadw_mass, _lepw_mass, hitfit::adjust_e_for_mass(), hitfit::Constrained_Top::constrain(), gather_cfg::cout, hitfit::Top_Decaykin::dump_ev(), hitfit::Top_Decaykin::hadt(), hitfit::Top_Decaykin::hadw(), hitfit::Top_Decaykin::lept(), m, hitfit::Lepjets_Event::met(), hitfit::Top_Fit_Args::print_event_flag(), hitfit::Top_Decaykin::solve_nu(), hitfit::Top_Decaykin::solve_nu_tmass(), and hitfit::Top_Fit_Args::solve_nu_tmass().

Referenced by fit(), and hitfit::RunHitFit< AElectron, AMuon, AJet, AMet >::FitAllPermutation().

{
  mt = 0;
  sigmt = 0;

  // Find the neutrino solutions by requiring either:
  // 1) that the leptonic top have the same mass as the hadronic top.
  // 2) that the mass of the lepton and neutrino is equal to the W mass

  umwhad = Top_Decaykin::hadw (ev) . m();
  double umthad = Top_Decaykin::hadt (ev) . m();
  double nuz1, nuz2;

  if (_args.solve_nu_tmass()) {
      Top_Decaykin::solve_nu_tmass (ev, umthad, nuz1, nuz2);
  }
  else {
      Top_Decaykin::solve_nu (ev, _lepw_mass, nuz1, nuz2);
  }

  // Set up to use the selected neutrino solution
  if (!nuz) {
      ev.met().setZ(nuz1);
  }
  else {
      ev.met().setZ(nuz2);
  }

  // Note: We have set the neutrino Pz, but we haven't set the neutrino energy.
  // Remember that originally the neutrino energy was equal to
  // sqrt(nu_px*nu_px + nu_py*nu_py).  Calculating the invariant mass squared
  // for the neutrino will give negative mass squared.
  // Therefore we need to adjust (increase) the neutrino energy in order to
  // make its mass remain zero.

  adjust_e_for_mass(ev.met(),0);

  // Find the unfit top mass as the average of the two sides.
  double umtlep = Top_Decaykin::lept (ev) . m();
  utmass = (umthad + umtlep) / 2;

  // Trace, if requested.
  if (_args.print_event_flag()) {
    cout << "Top_Fit::fit_one_perm() : Before fit:\n";
    Top_Decaykin::dump_ev (cout, ev);
  }

  // Maybe reject this event.
  if (_hadw_mass > 0 && test_for_bad_masses (ev, _args, umwhad,
                                             umthad, umtlep))
  {
    cout << "Top_Fit: bad mass comb.\n";
    return -999;
  }

  // Do the fit.
  double chisq = _constrainer.constrain (ev, mt, sigmt, pullx, pully);

  // Trace, if requested.
  if (_args.print_event_flag()) {
    cout << "Top_Fit::fit_one_perm() : After fit:\n";
    cout << "chisq: " << chisq << " mt: " << mt << " ";
    Top_Decaykin::dump_ev (cout, ev);
  }

  // Done!
  return chisq;
}

Friends And Related Function Documentation

std::ostream& operator<< ( std::ostream &  s, const Top_Fit &  fitter  )

friend

Output stream operator, print the content of this Top_Fit object to an output stream.

Parameters

s	The output stream to which to write.
fitter	The instance of Top_Fit to be printed.

Definition at line 593 of file Top_Fit.cc.

{
  return s << fitter._constrainer;
}

Member Data Documentation

const Top_Fit_Args hitfit::Top_Fit::_args

private

Definition at line 327 of file Top_Fit.h.

Referenced by Vispa.Main.Application.Application::_readCommandLineAttributes(), args(), fit(), and fit_one_perm().

Constrained_Top hitfit::Top_Fit::_constrainer

private

Definition at line 328 of file Top_Fit.h.

Referenced by fit_one_perm(), and hitfit::operator<<().

double hitfit::Top_Fit::_hadw_mass

private

Definition at line 330 of file Top_Fit.h.

Referenced by fit_one_perm().

double hitfit::Top_Fit::_lepw_mass

private

Definition at line 329 of file Top_Fit.h.

Referenced by fit_one_perm().