Rivet analyses

title: MARKIII_1987_I244856

$e^+e^-\to D^\pm_sD^{*\mp}_s$ cross section at $\sqrt{s}=4.14\,$GeV

Experiment: MARKIII (SPEAR)

Inspire ID: 244856

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 58 (1987) 2171

Beams: e+ e-

Beam energies: (2.1, 2.1)GeV

Run details: - e+e- > hadrons

$e^+e^-\to D^\pm_sD^{*\mp}_s$ cross section at $\sqrt{s}=4.14\,$GeV

Source code:MARKIII_1987_I244856.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief e+e-> D_s D_s* class MARKIII_1987_I244856 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(MARKIII_1987_I244856);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  declare(FinalState(), "FS");
  declare(UnstableParticles(Cuts::abspid == 431 or Cuts::abspid == 433), "UFS");
  // histos
  book(_h, 1, 1, 1);
}

void findChildren(const Particle& p, map<long, int>& nRes, int& ncount) {
  for (const Particle& child : p.children()) {
    if (child.children().empty()) {
      nRes[child.pid()] -= 1;
      --ncount;
    }
    else {
      findChildren(child, nRes, ncount);
    }
  }
}

/// Perform the per-event analysis
void analyze(const Event& event) {
  const FinalState& fs = apply<FinalState>(event, "FS");
  // total hadronic and muonic cross sections
  map<long, int> nCount;
  int ntotal(0);
  for (const Particle& p : fs.particles()) {
    nCount[p.pid()] += 1;
    ++ntotal;
  }
  // mu+mu- + photons
  if (nCount[-13] == 1 and nCount[13] == 1 && ntotal == 2 + nCount[22]) vetoEvent;
  Particles ds = apply<UnstableParticles>(event, "UFS").particles();
  for (const Particle& p1 : ds) {
    if (p1.abspid() != 431) continue;
    // find the children
    bool matched = false;
    map<long, int> nRes = nCount;
    int ncount = ntotal;
    findChildren(p1, nRes, ncount);
    for (const Particle& p2 : ds) {
      if (p2.abspid() != 433 || p1.pid() * p2.pid() > 0) continue;
      map<long, int> nRes2 = nRes;
      int ncount2 = ncount;
      findChildren(p2, nRes2, ncount2);
      if (ncount2 != 0) continue;
      matched = true;
      for (const auto& val : nRes2) {
        if (val.second != 0) {
          matched = false;
          break;
        }
      }
      if (matched) {
        break;
      }
    }
    if (matched) {
      _h->fill("4.14"s);
      break;
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  const double br = 0.045;
  const double fact = br * crossSection() / sumOfWeights() / picobarn;
  scale(_h, fact);
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _h;
/// @}

};

RIVET_DECLARE_PLUGIN(MARKIII_1987_I244856);

} ```