Rivet analyses

title: BELLE_2011_I878228

$e^+e^-\to D^{()+}_sD^{()-}_s$ cross sections near threshold

Experiment: BELLE (KEKB)

Inspire ID: 878228

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev. D83 (2011) 011101

Beams: e+ e-

Beam energies: ANY

Run details: - e+e- to hadrons, plus muons for normalisation of R

$e^+e^-\to D^{()+}_sD^{()-}_s$ cross sections measured near threshold by BELLE using ISR. Cross sections for individual states, and $R$ for the sum

Source code:BELLE_2011_I878228.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief e+e- > Ds()+ Ds()- class BELLE_2011_I878228 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2011_I878228);


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

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

  // Initialise and register projections
  declare(FinalState(), "FS");
  declare(UnstableParticles(), "UFS");

  // Book histograms
  book(_c["DpDm"], "/TMP/sigma_DpDm", refData(1, 1, 1));
  book(_c["DpDmS"], "/TMP/sigma_DpDmS", refData(1, 1, 2));
  book(_c["DpSDmS"], "/TMP/sigma_DpSDmS", refData(1, 1, 3));
  book(_c["All"], "/TMP/sigma_All", refData(2, 1, 1));
  book(_c["mu"], "/TMP/sigma_mu", refData(2, 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]) {
    _c["mu"]->fill(sqrtS());
    return;
  }
  // unstable charm analysis

  Particles ds = apply<UnstableParticles>(event, "UFS")
                     .particles(Cuts::abspid == 431 || Cuts::abspid == 433);
  for (unsigned int ix = 0; ix < ds.size(); ++ix) {
    const Particle& p1 = ds[ix];
    int id1 = abs(p1.pid());
    // check fs
    bool fs = true;
    for (const Particle& child : p1.children()) {
      if (child.pid() == p1.pid()) {
        fs = false;
        break;
      }
    }
    if (!fs) continue;
    // find the children
    map<long, int> nRes = nCount;
    int ncount = ntotal;
    findChildren(p1, nRes, ncount);
    bool matched = false;
    int sign = p1.pid() / id1;
    // loop over the other fs particles
    for (unsigned int iy = ix + 1; iy < ds.size(); ++iy) {
      const Particle& p2 = ds[iy];
      fs = true;
      for (const Particle& child : p2.children()) {
        if (child.pid() == p2.pid()) {
          fs = false;
          break;
        }
      }
      if (!fs) continue;
      if (p2.pid() / abs(p2.pid()) == sign) continue;
      int id2 = abs(p2.pid());
      if (!p2.parents().empty() && p2.parents()[0].pid() == p1.pid()) {
        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) {
        if (id1 == 431 && id2 == 431) {
          _c["DpDm"]->fill(sqrtS());
        }
        else if (id1 == 433 && id2 == 433) {
          _c["DpSDmS"]->fill(sqrtS());
        }
        else if ((id1 == 431 && id2 == 433) || (id1 == 433 && id2 == 431)) {
          _c["DpDmS"]->fill(sqrtS());
        }
        _c["All"]->fill(sqrtS());
        break;
      }
    }
    if (matched) break;
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_c, crossSection() / sumOfWeights() / nanobarn);
  size_t idx = 0;
  for (const string& s : {"DpDm"s, "DpDmS"s, "DpSDmS"s}) {
    Estimate1DPtr mult;
    book(mult, 1, 1, ++idx);
    barchart(_c[s], mult);
  }
  // R
  Estimate1DPtr mult;
  book(mult, 2, 1, 1);
  divide(_c["All"s], _c["mu"s], mult);
}

/// @}


/// @name Histograms
/// @{
map<string, Histo1DPtr> _c;
/// @}

};

RIVET_DECLARE_PLUGIN(BELLE_2011_I878228);

} ```