Rivet analyses

title: CMS_2011_I896211

$B^0$ cross section at 7 TeV

Experiment: CMS (LHC)

Inspire ID: 896211

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 106 (2011) 252001 - arXiv: 1104.2892 - Expt page: CMS-BPH-10-005

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - bottom meson production

Measurement of the cross section for the production of $B^0$ mesons at 7 TeV by the CMS experiment.

Source code:CMS_2011_I896211.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B0 production class CMS_2011_I896211 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2011_I896211);


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

/// Book histograms and initialise projections before the run
void init() {
  // projection
  declare(UnstableParticles(), "UFS");
  // histograms
  book(_h_total, 1, 1, 1);
  book(_h_pT, 2, 1, 1);
  book(_h_y, 3, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  if (_edges.empty()) _edges = _h_total->xEdges();
  // Final state of unstable particles to get particle spectra
  const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
  // loop over onium states
  for (const Particle& p : ufs.particles(Cuts::abspid == 511)) {
    // cuts on pT and rapidity
    const double y = p.absrap();
    const double pT = p.perp();
    if (pT < 5. || y > 2.4) continue;
    _h_total->fill(_edges[0]);
    _h_pT->fill(pT);
    _h_y->fill(y);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  double fact = 0.5 * crossSection() / microbarn / sumOfWeights();
  scale(_h_total, fact);
  scale(_h_pT, fact);
  // 0.5 due +/- y
  scale(_h_y, 0.5 * fact);
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<string> _h_total;
Histo1DPtr _h_pT, _h_y;
vector<string> _edges;
/// @}

};

RIVET_DECLARE_PLUGIN(CMS_2011_I896211);

} ```