Rivet analyses

title: CMS_2010_I845323

Charged-particle pT and pseudorapidity spectra from pp collisions at 900 and 2360 GeV.

Experiment: CMS (LHC)

Inspire ID: 845323

Status: VALIDATED

Authors: - A. Knutsson

References: - JHEP 02 (2010) 041 - DOI: 10.1007/JHEP02(2010)041 - arXiv: 1002.0621

Beams: p+ p+

Beam energies: (450.0, 450.0); (1180.0, 1180.0)GeV

Run details: - Non-single-diffractive (NSD) events only. Should include double-diffractive (DD) events and non-diffractive (ND) events but NOT single-diffractive (SD) events. Examples, in Pythia6 the SD processes to be turned off are 92 and 93, and in Pythia8 the SD processes are 103 and 104 (also called SoftQCD:singleDiffractive).

Charged particle spectra are measured in proton-proton collisions at center-of-mass energies 900 and 2360 GeV. The spectra are normalized to all non-single-diffractive (NSD) events using corrections for trigger and selection efficiency, acceptance, and branching ratios. There are transverse-momentum (pT) spectra from 0.1 to 2 GeV in bins of pseudorapidity (eta) and pT spectra from 0.1 to 4 GeV for |eta|<2.4. The eta spectra come from the average of three methods and cover |eta|<2.5 and are corrected to include all pT. The data were corrected according to the SD/DD/ND content of the CMS trigger, as predicted by PYTHIA6. The uncertainties connected with correct or incorrect modelling of diffraction were included in the systematic errors.

Source code:CMS_2010_I845323.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

namespace Rivet {

/// Charged-particle pT and pseudorapidity spectra from pp collisions at 900 and 2360 GeV class CMS_2010_I845323 : public Analysis { public:

RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2010_I845323);


/// @{

void init() {
  ChargedFinalState cfs(Cuts::abseta < 2.5);
  declare(cfs, "CFS");

  for (double eVal : allowedEnergies()) {
    const string en = toString(round(eVal));
    if (isCompatibleWithSqrtS(eVal)) _sqs = en;
    bool offset(en == "2360"s);

    for (int d = 0; d < 3; ++d) {
      for (int y = 0; y < 4; ++y) {
        size_t bin = 4 * d + y;
        book(_h[en + "dNch_dpT" + toString(bin)], d + (offset ? 4 : 1), 1, y + 1);
      }
    }
    book(_h[en + "dNch_dpT_all"], 7, 1, 1 + offset);
    book(_h[en + "dNch_dEta"], 8, 1, 1 + offset);
  }
  raiseBeamErrorIf(_sqs.empty());
}


void analyze(const Event& event) {

  //charged particles
  const ChargedFinalState& charged = apply<ChargedFinalState>(event, "CFS");

  for (const Particle& p : charged.particles()) {
    //selecting only charged hadrons
    if (!PID::isHadron(p.pid())) continue;

    const double pT = p.pT();
    const double eta = p.eta();

    // The data is actually a duplicated folded distribution. This should mimic it.
    _h[_sqs + "dNch_dEta"]->fill(eta, 0.5);
    _h[_sqs + "dNch_dEta"]->fill(-eta, 0.5);
    if (fabs(eta) < 2.4 && pT > 0.1 * GeV) {
      if (pT < 4.0 * GeV) {
        _h[_sqs + "dNch_dpT_all"]->fill(pT / GeV, 1.0 / (pT / GeV));
        if (pT < 2.0 * GeV) {
          const string suff = toString(int(fabs(eta) / 0.2));
          _h[_sqs + "dNch_dpT" + suff]->fill(pT / GeV);
        }
      }
    }
  }
}


void finalize() {
  const double normfac = 1.0 / sumOfWeights(); // Normalizing to unit eta is automatic
  // The pT distributions in bins of eta must be normalized to unit eta.  This is a factor of 2
  // for the |eta| times 0.2 (eta range).
  // The pT distributions over all eta are normalized to unit eta (2.0*2.4) and by 1/2*pi*pT.
  // The 1/pT part is taken care of in the filling.  The 1/2pi is taken care of here.
  const double normpT = normfac / (2.0 * 0.2);
  const double normpTall = normfac / (2.0 * M_PI * 2.0 * 2.4);

  for (auto& item : _h) {
    if (item.first.find("_dEta") != string::npos) {
      scale(item.second, normfac);
    }
    else if (item.first.find("_all") != string::npos) {
      scale(item.second, normpTall);
    }
    else {
      scale(item.second, normpT);
    }
  }
}

/// @}

private:

/// @{
map<string, Histo1DPtr> _h;

string _sqs = "";
/// @}

};

RIVET_DECLARE_ALIASED_PLUGIN(CMS_2010_I845323, CMS_2010_S8547297);

} ```

Aliases: - CMS_2010_S8547297