Rivet analyses

title: BABAR_2007_I747875

$e^+e^- \to$ $K^+K^-\pi^+\pi^-$, $K^+K^-\pi^0\pi^0$ and $K^+K^-K^+K^-$ cross-sections between 1.4 and 4 GeV

Experiment: BABAR (PEP-II)

Inspire ID: 747875

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev. D76 (2007) 012008, 2007

Beams: e+ e-

Beam energies: ANY

Run details: - e+e- to hadrons

Measurement of the cross section for $e^+e^- \to$ $K^+K^-\pi^+\pi^-$, $K^+K^-\pi^0\pi^0$ and $K^+K^-K^+K^-$ via radiative return, including the identification of $K^{*0}$, $\phi$ and $f_0(980)$ mesons for energies between 1.4 and 4. GeV

Source code:BABAR_2007_I747875.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief Add a short analysis description here class BABAR_2007_I747875 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2007_I747875);


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

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

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

  book(_cKpKmpippim, "TMP/KpKmpippim");
  book(_cKstarKpi, "TMP/KstarKpi");
  book(_cphipippim, "TMP/phipippim");
  book(_cphif0, "TMP/phif0");
  book(_cKpKmpi0pi0, "TMP/KpKmpi0pi0");
  book(_cphif0pi0pi0, "TMP/phif0pi0pi0");
  book(_c2Kp2Km, "TMP/2Kp2Km");
}

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");

  map<long, int> nCount;
  int ntotal(0);
  for (const Particle& p : fs.particles()) {
    nCount[p.pid()] += 1;
    ++ntotal;
  }
  const FinalState& ufs = apply<FinalState>(event, "UFS");
  for (const Particle& p : ufs.particles()) {
    if (p.children().empty()) continue;
    // K*0
    if (abs(p.pid()) == 313) {
      map<long, int> nRes = nCount;
      int ncount = ntotal;
      findChildren(p, nRes, ncount);
      // K* K+/- pi-/+
      if (ncount != 2) continue;
      bool matched = true;
      for (const auto& val : nRes) {
        if (abs(val.first) == 321 || abs(val.first) == 211) {
          continue;
        }
        else if (val.second != 0) {
          matched = false;
          break;
        }
      }
      if (matched == false) continue;
      if ((nCount[321] == 1 && nCount[-321] == 0 && nCount[211] == 0 && nCount[-211] == 1)
          || (nCount[321] == 0 && nCount[-321] == 1 && nCount[211] == 1 && nCount[-211] == 0))
        _cKstarKpi->fill();
    }
    else if (p.pid() == 333) {
      map<long, int> nRes = nCount;
      int ncount = ntotal;
      findChildren(p, nRes, ncount);
      // phi pi+pi-
      if (ncount == 2) {
        bool matched = true;
        for (const auto& val : nRes) {
          if (abs(val.first) == 211) {
            if (val.second != 1) {
              matched = false;
              break;
            }
          }
          else if (val.second != 0) {
            matched = false;
            break;
          }
        }
        if (matched) _cphipippim->fill();
      }
      for (const Particle& p2 : ufs.particles()) {
        if (p2.pid() != 9010221) continue;
        if (p2.parents()[0].isSame(p)) continue;
        map<long, int> nResB = nRes;
        int ncountB = ncount;
        findChildren(p2, nResB, ncountB);
        if (ncountB != 0) continue;
        bool matched2 = true;
        for (const auto& val : nResB) {
          if (val.second != 0) {
            matched2 = false;
            break;
          }
        }
        if (matched2) {
          _cphif0pi0pi0->fill();
          _cphif0->fill();
        }
      }
    }
  }
  if (ntotal == 4) {
    if (nCount[321] == 1 && nCount[-321] == 1 && nCount[211] == 1 && nCount[-211] == 1)
      _cKpKmpippim->fill();
    else if (nCount[321] == 1 && nCount[-321] == 1 && nCount[111] == 2)
      _cKpKmpi0pi0->fill();
    else if (nCount[321] == 2 && nCount[-321] == 2)
      _c2Kp2Km->fill();
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  for (unsigned int ix = 1; ix < 8; ++ix) {
    double sigma = 0., error = 0.;
    if (ix == 1) {
      sigma = _cKpKmpippim->val();
      error = _cKpKmpippim->err();
    }
    else if (ix == 2) {
      sigma = _cKstarKpi->val();
      error = _cKstarKpi->err();
    }
    else if (ix == 3) {
      sigma = _cphipippim->val();
      error = _cphipippim->err();
    }
    else if (ix == 4) {
      sigma = _cphif0->val();
      error = _cphif0->err();
    }
    else if (ix == 5) {
      sigma = _cKpKmpi0pi0->val();
      error = _cKpKmpi0pi0->err();
    }
    else if (ix == 6) {
      sigma = _cphif0pi0pi0->val();
      error = _cphif0pi0pi0->err();
    }
    else if (ix == 7) {
      sigma = _c2Kp2Km->val();
      error = _c2Kp2Km->err();
    }
    sigma *= crossSection() / sumOfWeights() / nanobarn;
    error *= crossSection() / sumOfWeights() / nanobarn;

    Estimate1DPtr mult;
    book(mult, ix, 1, 1);
    for (auto& b : mult->bins()) {
      if (inRange(sqrtS() / GeV, b.xMin(), b.xMax())) {
        b.set(sigma, error);
      }
    }
  }
}

/// @}


/// @name Histograms
/// @{
CounterPtr _cKpKmpippim, _cKstarKpi, _cphipippim, _cphif0, _cKpKmpi0pi0, _cphif0pi0pi0, _c2Kp2Km;
/// @}

};

RIVET_DECLARE_PLUGIN(BABAR_2007_I747875);

} ```