Rivet analyses

title: CMS_2012_I1089835

Inclusive b-jet production in pp collisions at 7 TeV

Experiment: CMS (LHC)

Inspire ID: 1089835

Status: VALIDATED

Authors: - cms-pag-conveners-bph@cern.ch - Paolo Gunnellini

References: - Expt page: CMS-BPH-11-022 - JHEP 1204 (2012) 084 - DOI:10.1007/JHEP04(2012)084 - arXiv: 1202.4617

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - QCD events with transverse momentum greater than 10 GeV

The inclusive b-jet production cross section in pp collisions at a center-of-mass energy of 7 TeV is measured using data collected by the CMS experiment at the LHC. The cross section is presented as a function of the jet transverse momentum in the range 18 $<$ pT $<$ 200 GeV for several rapidity intervals. The results are also given as the ratio of the b-jet production cross section to the inclusive jet production cross section. The measurement is performed with two different analyses, which differ in their trigger selection and b-jet identification: a jet analysis that selects events with a b jet using a sample corresponding to an integrated luminosity of 34 inverse picobarns, and a muon analysis requiring a b jet with a muon based on an integrated luminosity of 3 inverse picobarns. In both approaches the b jets are identified by requiring a secondary vertex. The results from the two methods are in agreement with each other and with next-to-leading order calculations, as well as with predictions based on the PYTHIA event generator.

Source code:CMS_2012_I1089835.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Tools/Logging.hh"

namespace Rivet {

/// @brief Inclusive b-jet production in pp collisions at 7 TeV class CMS_2012_I1089835 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2012_I1089835);


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

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

  const FinalState cnfs;
  declare(cnfs, "FS");
  declare(FastJets(cnfs, JetAlg::ANTIKT, 0.5), "Jets");

  book(_h_dsigdpty05, 4, 1, 1);
  book(_h_dsigdpty10, 5, 1, 1);
  book(_h_dsigdpty15, 6, 1, 1);
  book(_h_dsigdpty20, 7, 1, 1);
  book(_h_dsigdpty22, 8, 1, 1);
}


/// Perform the per-event analysis
void analyze(const Event& event) {

  const FastJets& fastjets = apply<FastJets>(event, "Jets");
  const Jets jets = fastjets.jetsByPt(Cuts::pT > 10 * GeV);

  for (const Jet& j : jets) {

    const double ptB = j.pT();
    const double yB = j.rapidity();

    if (j.bTagged()) {

      if (fabs(yB) < 0.5) {
        _h_dsigdpty05->fill(ptB, 1.0);
      }
      else if (fabs(yB) >= 0.5 && fabs(yB) < 1.0) {
        _h_dsigdpty10->fill(ptB, 1.0);
      }
      else if (fabs(yB) >= 1.0 && fabs(yB) < 1.5) {
        _h_dsigdpty15->fill(ptB, 1.0);
      }
      else if (fabs(yB) >= 1.5 && fabs(yB) < 2.0) {
        _h_dsigdpty20->fill(ptB, 1.0);
      }
      else if (fabs(yB) >= 2.0 && fabs(yB) < 2.2) {
        _h_dsigdpty22->fill(ptB, 1.0);
      }
    }
  }
}

/// Normalise histograms etc., after the run
void finalize() {

  double invlumi = crossSection() / picobarn / sumOfWeights();

  scale(_h_dsigdpty05, invlumi);
  scale(_h_dsigdpty10, invlumi);
  scale(_h_dsigdpty15, invlumi);
  scale(_h_dsigdpty20, invlumi);
  scale(_h_dsigdpty22, invlumi / 0.4);
}

/// @}

private:

/// @name Histograms
/// @{
Histo1DPtr _h_dsigdpty05;
Histo1DPtr _h_dsigdpty10;
Histo1DPtr _h_dsigdpty15;
Histo1DPtr _h_dsigdpty20;
Histo1DPtr _h_dsigdpty22;
/// @}

};

RIVET_DECLARE_PLUGIN(CMS_2012_I1089835);

} ```