Rivet analyses

title: ATLAS_2010_I849050

Charged particles at 900 GeV in ATLAS

Experiment: ATLAS (LHC 900GeV)

Inspire ID: 849050

Status: VALIDATED

Authors: - Frank Siegert

References: - Expt page: ATLAS-STDM-2010-01 - arXiv: 1003.3124

Beams: p+ p+

Beam energies: (450.0, 450.0)GeV

Run details: - pp QCD interactions at 900 GeV including diffractive events.

The first measurements with the ATLAS detector at the LHC. Data were collected using a minimum-bias trigger in December 2009 during proton-proton collisions at a centre of mass energy of 900 GeV. The charged- particle density, its dependence on transverse momentum and pseudorapid- ity, and the relationship between transverse momentum and charged-particle multiplicity are measured for events with at least one charged particle in the kinematic range $|\eta| < 2.5$ and $p_\perp > 500$ MeV. All data is corrected to the particle level.

Source code:ATLAS_2010_I849050.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

namespace Rivet {

/// @brief ATLAS minimum bias analysis at 900 GeV /// @author Frank Siegert class ATLAS_2010_I849050 : public Analysis { public:

RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2010_I849050);


void init() {
  ChargedFinalState cfs((Cuts::etaIn(-2.5, 2.5) && Cuts::pT >= 0.5 * GeV));
  declare(cfs, "CFS");

  book(_h_dNch_deta, 2, 1, 1);
  book(_h_dNch_dpT, 3, 1, 1);
  book(_h_dNevt_dNch, 4, 1, 1);
  book(_p_meanpT_Nch, 5, 1, 1);

  book(_Nevt_after_cuts, "nevt_pass");
}


void analyze(const Event& event) {
  const ChargedFinalState& charged = apply<ChargedFinalState>(event, "CFS");
  if (charged.size() < 1) {
    vetoEvent;
  }
  _Nevt_after_cuts->fill();

  _h_dNevt_dNch->fill(charged.size());
  for (const Particle& p : charged.particles()) {
    double pT = p.pT() / GeV;
    _h_dNch_deta->fill(p.eta());
    _h_dNch_dpT->fill(pT, 1.0 / pT);
    _p_meanpT_Nch->fill(charged.size(), pT);
  }
}


void finalize() {
  double deta = 5.0;
  scale(_h_dNch_deta, 1.0 / _Nevt_after_cuts->val());
  scale(_h_dNch_dpT, 1.0 / _Nevt_after_cuts->val() / TWOPI / deta);
  scale(_h_dNevt_dNch, 1.0 / _Nevt_after_cuts->val());
}

private:

Histo1DPtr _h_dNch_deta;
Histo1DPtr _h_dNch_dpT;
Histo1DPtr _h_dNevt_dNch;
Profile1DPtr _p_meanpT_Nch;

CounterPtr _Nevt_after_cuts;

};

RIVET_DECLARE_ALIASED_PLUGIN(ATLAS_2010_I849050, ATLAS_2010_S8591806);

} ```

Aliases: - ATLAS_2010_S8591806