gentop.h

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//
//
// File: hitfit/gentop.h
// Purpose: Toy ttbar event generator for testing.
// Created: Jul, 2000, sss.
//
// This is a very simple event generator for ttbar events, to allow some
// basic tests of the mass fitting code.  We generate random ttbars,
// with kinematics pulled out of a hat, and then decay them into l+jets
// events.  No radiation or other such luxuries, and, as mentioned, any
// kinematic distribuions will certainly be wrong.  But the generated
// events should satisfy the l+jets mass constraints.
//
// CMSSW File      : interface/gentop.h
// Original Author : Scott Stuart Snyder <snyder@bnl.gov> for D0
// Imported to CMSSW by Haryo Sumowidagdo <Suharyo.Sumowidagdo@cern.ch>
//

#include <string>
#include <iosfwd>

#include "CLHEP/Random/Random.h"

namespace hitfit {

  class Defaults;
  class Lepjets_Event;

  class Gentop_Args
  //
  // Hold on to parameters for the toy event generator.
  //   float mt           - Generated top mass.
  //   float sigma_mt     - Width of top mass distribution.
  //
  //   float mh           - Generated Higgs mass.
  //   float sigma_mh     - Width of Higgs mass distribution.
  //
  //   float mw           - Generated W mass.
  //   float sigma_mw     - Width of W mass distribution.
  //
  //   float mb           - Generated b mass.
  //   float sigma_mb     - Width of b mass distribution.
  //
  //   float t_pt_mean    - Mean pt of the generated top quarks.
  //                        (It will be drawn from an exponential distribution.)
  //   float recoil_pt_mean-Mean pt of ttbar system.
  //                        (It will be drawn from an exponential distribution.)
  //   float boost_sigma  - Width of z-boost of ttbar system.
  //   float m_boost      - Mass of z-boost of ttbar system.
  //   float sxv_tageff   - Assumed efficiency of SVX b-tag.
  //   bool smear         - If true, smear the event.
  //   bool smear_dir     - If false, smear only energies, not directions.
  //   bool muon          - If false, decay leptonic ts into electrons.
  //                        Otherwise, decay into muons.
  //   string ele_res_str - Electron resolution, for Vector_Resolution.
  //   string muo_res_str - Muon resolution, for Vector_Resolution.
  //   string jet_res_str - Jet resolution, for Vector_Resolution.
  //   string kt_res_str  - Kt resolution, for Resolution.
  //
  {
  public:
    // Constructor.  Initialize from a Defaults object.
    Gentop_Args(const Defaults& defs);

    // Retrieve parameter values.

    double t_pt_mean() const;

    double mt() const;

    double sigma_mt() const;

    double mh() const;

    double sigma_mh() const;

    double recoil_pt_mean() const;

    double boost_sigma() const;

    double m_boost() const;

    double mb() const;

    double sigma_mb() const;

    double mw() const;

    double sigma_mw() const;

    double svx_tageff() const;

    bool smear() const;

    bool smear_dir() const;

    bool muon() const;

    std::string ele_res_str() const;

    std::string muo_res_str() const;

    std::string jet_res_str() const;

    std::string kt_res_str() const;

  private:
    // Hold on to parameter values.

    double _t_pt_mean;

    double _mt;

    double _sigma_mt;

    double _mh;

    double _sigma_mh;

    double _recoil_pt_mean;

    double _boost_sigma;

    double _m_boost;

    double _mb;

    double _sigma_mb;

    double _mw;

    double _sigma_mw;

    double _svx_tageff;

    bool _smear;

    bool _smear_dir;

    bool _muon;

    std::string _ele_res_str;

    std::string _muo_res_str;

    std::string _jet_res_str;

    std::string _kt_res_str;
  };

  // Generate a ttbar -> ljets event.
  Lepjets_Event gentop(const Gentop_Args& args, CLHEP::HepRandomEngine& engine);

  // Generate a ttH -> ljets+bb event.
  Lepjets_Event gentth(const Gentop_Args& args, CLHEP::HepRandomEngine& engine);

}  // namespace hitfit