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CMS_2017_I1608166

Measurement of charged pion, kaon, and proton production in proton-proton collisions at 13 TeV
Experiment: CMS (LHC)
Inspire ID: 1608166
Status: VALIDATED
Authors:
  • Markus Seidel
References:
  • Phys. Rev. D 96, 112003 (201
  • DOI:10.1103/PhysRevD.96.112003
  • arXiv: 1706.10194
  • Public page: FSQ-16-004
Beams: p+ p+
Beam energies: (6500.0, 6500.0) GeV
Run details:
  • Minimum Bias inelastic collisions

Transverse momentum spectra of charged pions, kaons, and protons are measured in proton-proton collisions at sqrt(s)=13 TeV with the CMS detector at the LHC. The particles, identified via their energy loss in the silicon tracker, are measured in the transverse momentum range of pT = 0.1-1.7 GeV/c and rapidities |y|<1. The pT spectra and integrated yields are compared to previous results at smaller sqrt(s) and to predictions of Monte Carlo event generators. The average pT increases with particle mass and charged particle multiplicity of the event. Comparisons with previous CMS results at s=0.9, 2.76, and 7 TeV show that the average pT and the ratios of hadron yields feature very similar dependences on the particle multiplicity in the event, independently of the center-of-mass energy of the pp collision.

Source code: CMS_2017_I1608166.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/ChargedFinalState.hh"
  4#include "Rivet/Tools/ParticleName.hh"
  5
  6namespace Rivet {
  7
  8
  9  /// Measurement of charged pion, kaon, and proton production in 13 TeV pp collisions
 10  class CMS_2017_I1608166 : public Analysis {
 11  public:
 12
 13    /// Constructor
 14    RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2017_I1608166);
 15
 16
 17    /// @name Analysis methods
 18    //@{
 19
 20    /// Book histograms and initialise projections before the run
 21    void init() {
 22      const ChargedFinalState cfs(Cuts::absrap < 1.);
 23      declare(cfs, "CFS");
 24      //
 25      // pt spectra
 26      book(_h[PID::PIPLUS],  "d01-x01-y01");
 27      book(_h[PID::KPLUS],   "d01-x01-y02");
 28      book(_h[PID::PROTON],  "d01-x01-y03");
 29      book(_h[PID::PIMINUS], "d02-x01-y01");
 30      book(_h[PID::KMINUS],  "d02-x01-y02");
 31      book(_h[PID::PBAR],    "d02-x01-y03");
 32
 33      // negative/positive ratios
 34      book(_s["pi-/pi+"], "d43-x01-y01");
 35      book(_s["k-/k+"],   "d44-x01-y01");
 36      book(_s["p~/p"],    "d45-x01-y01");
 37
 38      // k/pi and p/pi ratios
 39      book(_hkpi[PID::PIPLUS], "TMP/hkpi/pi", refData(46, 1, 1));
 40      book(_hkpi[PID::KPLUS],  "TMP/hkpi/k",  refData(46, 1, 1));
 41      book(_hppi[PID::PIPLUS], "TMP/hppi/pi", refData(47, 1, 1));
 42      book(_hppi[PID::PROTON], "TMP/hppi/p",  refData(47, 1, 1));
 43      book(_s["k/pi"],    "d46-x01-y01");
 44      book(_s["p/pi"],    "d47-x01-y01");
 45    }
 46
 47
 48    void analyze(const Event& event) {
 49
 50      const ChargedFinalState& cfs = apply<ChargedFinalState>(event, "CFS");
 51      for (const Particle& p : cfs.particles()) {
 52
 53        // protections against MC generators decaying long-lived particles
 54        if (p.hasAncestor(310)  || p.hasAncestor(-310)  ||  // K0s
 55            p.hasAncestor(130)  || p.hasAncestor(-130)  ||  // K0l
 56            p.hasAncestor(3322) || p.hasAncestor(-3322) ||  // Xi0
 57            p.hasAncestor(3122) || p.hasAncestor(-3122) ||  // Lambda
 58            p.hasAncestor(3222) || p.hasAncestor(-3222) ||  // Sigma+/-
 59            p.hasAncestor(3312) || p.hasAncestor(-3312) ||  // Xi-/+
 60            p.hasAncestor(3334) || p.hasAncestor(-3334))    // Omega-/+
 61          continue;
 62
 63        if (theParticles.find(p.pid()) != theParticles.end()) {
 64          // fill pt spectra
 65          _h[p.pid()]->fill(p.pt() / GeV);
 66          // fill tmp histos for ratios
 67          if (p.abspid() != PID::PROTON)
 68            _hkpi[p.abspid()]->fill(p.pt() / GeV);
 69          if (p.abspid() != PID::KPLUS)
 70            _hppi[p.abspid()]->fill(p.pt() / GeV);
 71        }
 72
 73      }
 74
 75    }
 76
 77
 78    void finalize() {
 79
 80      divide(_h[PID::PIMINUS], _h[PID::PIPLUS], _s["pi-/pi+"]);
 81      divide(_h[PID::KMINUS],  _h[PID::KPLUS],  _s["k-/k+"]);
 82      divide(_h[PID::PBAR],    _h[PID::PROTON], _s["p~/p"]);
 83
 84      divide(_hkpi[PID::KPLUS],  _hkpi[PID::PIPLUS], _s["k/pi"]);
 85      divide(_hppi[PID::PROTON], _hppi[PID::PIPLUS], _s["p/pi"]);
 86
 87      scale(_h, 1./2./sumOfWeights());
 88
 89    }
 90
 91
 92    set<int> theParticles = {PID::PIPLUS, PID::KPLUS, PID::PROTON, PID::PIMINUS, PID::KMINUS, PID::PBAR};
 93
 94    map<int, Histo1DPtr> _h;
 95    map<int, Histo1DPtr> _hkpi, _hppi;
 96    map<string, Scatter2DPtr> _s;
 97
 98  };
 99
100
101  RIVET_DECLARE_PLUGIN(CMS_2017_I1608166);
102
103}