Rivet analyses

title: CMS_2013_I1225274

Measurements of the $\Upsilon(1S)$, $\Upsilon(2S)$, and $\Upsilon(3S)$ differential cross sections in pp collisions at $\sqrt{s}=7$ TeV

Experiment: CMS (LHC)

Inspire ID: 1225274

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett.B 727 (2013) 101-125 - arXiv: 1303.5900 - Expt page: CMS-BPH-11-001

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - Upsilon production at LHC energies

Measurement of the transverse momentum distribtions for $\Upsilon(1S)$, $\Upsilon(2S)$, and $\Upsilon(3S)$ production in six rapidity intervals. The production ratios are also measured. There is a more recent 7 TeV CMS measurement but this one extends to zero transverse momentum and has more rapidity intervals.

Source code:CMS_2013_I1225274.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief Upsilon(1,2,3S) at 7 TeV class CMS_2013_I1225274 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2013_I1225274);

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

/// Book histograms and initialise projections before the run
void init() {
  // projection
  declare(UnstableParticles(), "UFS");
  // histograms
  for (unsigned int ix = 0; ix < 3; ++ix) {
    if (ix < 2) book(_h_total[ix], 1, 1, 1 + ix);
    for (unsigned int iy = 0; iy < 2; ++iy) {
      book(_h_pT_y[ix][iy], {0., 0.4, 0.8, 1.2, 1.6, 2.0, 2.4});
      for (unsigned int iz = 0; iz < 6; ++iz) {
        book(_h_pT_y[ix][iy]->bin(iz + 1), 5 + 3 * iz + ix, 1, iy + 1);
      }
      book(_h_pT[ix][iy], 2 + ix, 1, iy + 1);
      book(_h_y[ix][iy], 23 + ix, 1, iy + 1);
      book(_h_r[ix][iy], "TMP/h_r_" + toString(ix) + "_" + toString(iy), refData(26, 1, iy + 1));
    }
    book(_h_pT_acc[ix], 29 + ix, 1, 1);
  }
}

void findChildren(const Particle& p, Particles& mum, Particles& mup, unsigned int& nstable) {
  for (const Particle& child : p.children()) {
    if (child.pid() == PID::MUON) {
      mum.push_back(child);
      ++nstable;
    }
    else if (child.pid() == PID::ANTIMUON) {
      mup.push_back(child);
      ++nstable;
    }
    else if (child.pid() == PID::PHOTON) {
      continue;
    }
    else if (child.children().empty()) {
      ++nstable;
    }
    else {
      findChildren(child, mum, mup, nstable);
    }
  }
}

// from eqn 1 of paper
bool acceptMuon(const Particle& p) const {
  const double abseta = p.abseta();
  const double xp = p.perp();
  if (abseta < 0.8)
    return xp > 3.75;
  else if (abseta < 1.6)
    return xp > 3.5;
  else if (abseta < 2.4)
    return xp > 3.0;
  else
    return false;
}

/// Perform the per-event analysis
void analyze(const Event& event) {
  if (_edges.empty()) _edges = _h_total[0]->xEdges();
  // Final state of unstable particles to get particle spectra
  const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");

  for (const Particle& p :
       ufs.particles(Cuts::pid == 553 || Cuts::pid == 100553 || Cuts::pid == 200553)) {
    const double absrap = p.absrap();
    // rapidity cut
    if (absrap > 2.4) continue;
    double xp = p.perp();
    unsigned int iloc = 0;
    if (p.pid() == 553)
      iloc = 0;
    else if (p.pid() == 100553)
      iloc = 1;
    else if (p.pid() == 200553)
      iloc = 2;
    // acceptance corrected only hist
    if (absrap < 1.2) {
      _h_pT_acc[iloc]->fill(xp);
    }
    // check if children muons and within acceptance
    unsigned int imin = 1;
    // find the children
    Particles mum, mup;
    unsigned int nstable(0);
    findChildren(p, mum, mup, nstable);
    if (mup.size() == 1 && mup.size() == 1 && nstable == 2) {
      if (acceptMuon(mup[0]) && acceptMuon(mum[0])) imin = 0;
    }
    // fill the histos
    for (unsigned int ix = imin; ix < 2; ++ix) {
      _h_pT_y[iloc][ix]->fill(absrap, xp);
      _h_pT[iloc][ix]->fill(xp);
      _h_r[iloc][ix]->fill(xp);
      if (xp < 50.) _h_y[iloc][ix]->fill(absrap);
      if (ix == 0) {
        _h_total[ix]->fill(_edges[iloc]);
      }
      else {
        _h_total[ix]->fill(_edges[iloc], _br[iloc]);
      }
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  double factor = crossSection() / nanobarn / sumOfWeights();
  for (unsigned int ix = 0; ix < 2; ++ix) {
    // total cross sections, just the factor
    scale(_h_total[ix], factor);
    for (unsigned int iy = 0; iy < 3; ++iy) {
      double factor2 = factor;
      if (ix == 1) factor2 *= _br[iy];
      // pT integrated over y, just the factor
      scale(_h_pT[iy][ix], factor2);
      scale(_h_r[iy][ix], factor2);
      if (ix == 1) scale(_h_pT_acc[iy], factor2);
      // not integrated over y, alsso undo y +/- folding
      scale(_h_y[iy][ix], 0.5 * factor2);
      scale(_h_pT_y[iy][ix], 0.5 * factor2);
      divByGroupWidth(_h_pT_y[iy][ix]);
    }
    // ratios
    Estimate1DPtr tmp;
    // ups 3/ ups1
    book(tmp, 26, 1, ix + 1);
    divide(_h_r[2][ix], _h_r[0][ix], tmp);
    // ups 2/ ups1
    book(tmp, 27, 1, ix + 1);
    divide(_h_r[1][ix], _h_r[0][ix], tmp);
    // ups 3/ ups2
    book(tmp, 28, 1, ix + 1);
    divide(_h_r[2][ix], _h_r[1][ix], tmp);
  }
}

///@}


/// @name Histograms
///@{
Histo1DGroupPtr _h_pT_y[3][2];
BinnedHistoPtr<string> _h_total[2];
Histo1DPtr _h_pT[3][2], _h_pT_acc[3], _h_y[3][2], _h_r[3][2];
vector<double> _br{0.0248, 0.0193, 0.0218};
vector<string> _edges;
///@}

};

RIVET_DECLARE_PLUGIN(CMS_2013_I1225274);

} ```