Rivet analyses

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/Sphericity.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief baryons at 34.8 and 42.1 GeV
  class TASSO_1989_I266893 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(TASSO_1989_I266893);

    /// @name Analysis methods
    /// @{

    /// Book histograms and initialise projections before the run
    void init() {

      // Initialise and register projections
      declare(Beam(), "Beams");
      declare(UnstableParticles(), "UFS");
      const ChargedFinalState cfs;
      declare(cfs, "CFS");
      declare(Sphericity(cfs), "Sphericity");

      // Book histograms
      size_t ih = 0;
      for (double eVal : allowedEnergies()) {
        const string en = toString(round(eVal / MeV));
        if (isCompatibleWithSqrtS(eVal)) _sqs = en;
        book(_h[en + "lam_p"], 6 * ih + 3, 1, 1);
        book(_h[en + "lam_pL"], 6 * ih + 4, 1, 1);
        book(_h[en + "lam_pTIn"], 6 * ih + 5, 1, 1);
        book(_h[en + "lam_pTOut"], 6 * ih + 6, 1, 1);
        book(_h[en + "lam_rap"], 6 * ih + 7, 1, 1);
        book(_h[en + "lam_x"], 6 * ih + 8, 1, 1);
        book(_p[en + "lam_S_1"], 15 + ih, 1, 1);
        book(_p[en + "lam_S_2"], 15 + ih, 1, 2);
        if (en == "34800"s) {
          book(_h["xi_p"], 18, 1, 1);
          book(_h["xi_pL"], 19, 1, 1);
          book(_h["xi_pTIn"], 20, 1, 1);
          book(_h["xi_pTOut"], 21, 1, 1);
          book(_h["xi_rap"], 22, 1, 1);
          book(_h["xi_x"], 23, 1, 1);
        }
        ++ih;
      }
      raiseBeamErrorIf(_sqs.empty());
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      const ChargedFinalState& cfs = apply<ChargedFinalState>(event, "CFS");
      const size_t numParticles = cfs.particles().size();

      // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
      if (numParticles < 2) vetoEvent;

      // Get beams and average beam momentum
      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
      const double meanBeamMom = 0.5 * (beams.first.p3().mod() + beams.second.p3().mod());
      const Sphericity& sphericity = apply<Sphericity>(event, "Sphericity");
      unsigned int nLam(0);
      UnstableParticles ufs = apply<UnstableParticles>(event, "UFS");
      for (const Particle& p : ufs.particles(Cuts::abspid == 3122 || Cuts::abspid == 3312)) {
        unsigned int id = p.abspid();
        double xE = p.E() / meanBeamMom;
        Vector3 mom3 = p.p3();
        const double energy = p.E();
        double modp = mom3.mod();
        double beta = modp / energy;
        const double momS = dot(sphericity.sphericityAxis(), mom3);
        const double pTinS = dot(mom3, sphericity.sphericityMajorAxis());
        const double pToutS = dot(mom3, sphericity.sphericityMinorAxis());
        const double rapidityS = 0.5 * std::log((energy + momS) / (energy - momS));
        if (id == 3122) {
          _h[_sqs + "lam_x"]->fill(xE, 1. / beta);
          _h[_sqs + "lam_p"]->fill(modp / GeV);
          _h[_sqs + "lam_pL"]->fill(abs(momS) / GeV);
          _h[_sqs + "lam_pTIn"]->fill(abs(pTinS) / GeV);
          _h[_sqs + "lam_pTOut"]->fill(abs(pToutS) / GeV);
          _h[_sqs + "lam_rap"]->fill(abs(rapidityS));
          ++nLam;
        }
        else if (_sqs == "34800"s) {
          _h["xi_x"]->fill(xE, 1. / beta);
          _h["xi_p"]->fill(modp / GeV);
          _h["xi_pL"]->fill(abs(momS) / GeV);
          _h["xi_pTIn"]->fill(abs(pTinS) / GeV);
          _h["xi_pTOut"]->fill(abs(pToutS) / GeV);
          _h["xi_rap"]->fill(abs(rapidityS));
        }
      }
      const double sphere = sphericity.sphericity();
      _p[_sqs + "lam_S_1"]->fill(sphere, nLam);
      _p[_sqs + "lam_S_2"]->fill(sphere, cfs.particles().size());
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      size_t ih = 0;
      Estimate1DPtr temp;
      scale(_h, crossSection() / nanobarn / sumOfWeights());
      for (double eVal : allowedEnergies()) {
        const string en = toString(round(eVal / MeV));
        scale(_h[en + "lam_x"], sqr(eVal));
        if (en == "34800"s) scale(_h["xi_x"], sqr(eVal));
        book(temp, 15 + ih, 1, 3);
        divide(_p[en + "lam_S_1"], _p[en + "lam_S_2"], temp);
        ++ih;
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    map<string, Histo1DPtr> _h;
    map<string, Profile1DPtr> _p;
    string _sqs = "";
    /// @}
  };


  RIVET_DECLARE_PLUGIN(TASSO_1989_I266893);
}