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ALICE_2021_I1848990

Measurement of beauty and charm production at 5 TeV
Experiment: ALICE (LHC)
Inspire ID: 1848990
Status: VALIDATED
Authors:
  • Yonne Lourens
  • Maria Monalisa De Melo Paulino
References: Beams: p+ p+
Beam energies: (2510.0, 2510.0) GeV
Run details:
  • Minimum bias events

The $p_\text{T}$-differential production cross sections of prompt and non-prompt (produced in beauty-hadron decays) D mesons were measured by the ALICE experiment at midrapidity ($|y|<0.5$) in proton-proton collisions at $\sqrt{s}$=5.02 TeV. The data sample used in the analysis corresponds to an integrated luminosity of $(19.3\pm0.4)$ nb${}^{-1}$. D mesons were reconstructed from their decays $D^0 \to K^-\pi^+$, $D^+\to K^-\pi^+\pi^+$, and $D^+_\text{s} \to \varphi\pi^+\to K^-K^+\pi^+$ and their charge conjugates. Compared to previous measurements in the same rapidity region, the cross sections of prompt $D^+$ and $D^+_\text{s}$ mesons have an extended $p_\text{T}$ coverage and total uncertainties reduced by a factor ranging from 1.05 to 1.6, depending on $p_\text{T}$, allowing for a more precise determination of their $p_\text{T}$-integrated cross sections. The results are well described by perturbative QCD calculations. The fragmentation fraction of heavy quarks to strange mesons divided by the one to non-strange mesons, $f_\text{s}/(f_\text{u}+f_\text{d})$, is compatible for charm and beauty quarks and with previous measurements at different centre-of-mass energies and collision systems. The $b\bar{b}$ production cross section per rapidity unit at midrapidity, estimated from non-prompt $D$-meson measurements, is $\text{d}\sigma_{b\bar{b}} / \text{d} y_{|y|<0.5}$ = 34.5 $\pm$ 2.4 (stat) ${}^{+4.7}_{-2.9}$ (tot. syst.) $\mu$b${}^{-1}$. It is compatible with previous measurements at the same centre-of-mass energy and with the cross section predicted by perturbative QCD calculations.

Source code: ALICE_2021_I1848990.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/UnstableParticles.hh"
  4
  5namespace Rivet {
  6
  7  /// @brief Measurement of beauty and charm production iat 5 TeV
  8  class ALICE_2021_I1848990 : public Analysis {
  9  public:
 10
 11    RIVET_DEFAULT_ANALYSIS_CTOR(ALICE_2021_I1848990);
 12
 13    void init() {
 14
 15      const UnstableParticles fs(Cuts::absrap < 0.5);
 16      declare(fs, "fs");
 17
 18      book(_h["npmD0"],    1, 1, 1); // non-prompt D0 production cross section
 19      book(_h["npmDplus"], 2, 1, 1); // non-prompt D+ production cross section
 20      book(_h["npmDS"],    3, 1, 1); // non-prompt DS+ production cross section
 21      book(_h["pmD0"],     4, 1, 1); // prompt D0 production cross section
 22      book(_h["pmDplus"],  5, 1, 1); // prompt D+ production cross section
 23      book(_h["pmDS"],     6, 1, 1); // prompt DS+ production cross section
 24
 25      book(_e["npmD0_pmD0"],           7, 1, 1); // ratio between non-prompt D0 and prompt D0
 26      book(_e["npmDplus_pmDplus"],     8, 1, 1); // ratio between non-prompt D+ and prompt D+
 27      book(_e["npmDS_pmDS"],           9, 1, 1); // ratio between non-prompt DS+ and prompt DS+
 28      book(_e["pmDplus_pmD0"],        10, 1, 1); // ratio between prompt D+ and prompt D0
 29      book(_e["npmDplus_npmD0"],      11, 1, 1); // ratio between non-prompt D+ and non-prompt D0
 30      book(_e["pmDS_pmDplusD0sum"],   12, 1, 1); // ratio between prompt DS+ and sum of prompt D0 and prompt D+
 31      book(_e["npmDS_npmDplusD0sum"], 13, 1, 1); // ratio between non-prompt DS+ and sum of non-prompt D0 and non-prompt D+
 32
 33      book(_h["pmDplusD0sum"],  "TMP/_pmDplusD0sum",  refData(12,1,1));
 34      book(_h["npmDplusD0sum"], "TMP/_npmDplusD0sum", refData(13,1,1));
 35
 36      book(_e_frag["pmDS_pmDpD0"], 14, 1, 1); // c-quark fragmentation-fraction ratio
 37      book(_h_frag["pmDS"], "TMP/_fpmDS", refData<YODA::BinnedEstimate<string>>(14,1,1));
 38      book(_h_frag["pmDpD0"], "TMP/_fpmDpD0", refData<YODA::BinnedEstimate<string>>(14,1,1));
 39
 40      book(_e_frag["npmDS_npmDpD0"], 15, 1, 1); // b-quark fragmentation-fraction ratio
 41      book(_h_frag["npmDS"], "TMP/_npmDS", refData<YODA::BinnedEstimate<string>>(15,1,1));
 42      book(_h_frag["npmDpD0"], "TMP/_npmDpD0", refData<YODA::BinnedEstimate<string>>(15,1,1));
 43
 44    }
 45
 46    void analyze(const Event& event) {
 47
 48      const UnstableParticles& fs = apply<UnstableParticles>(event, "fs");
 49
 50      for (const Particle& p : fs.particles()) {
 51        if (p.fromBottom()) {
 52          if (p.abspid() == PID::D0) {
 53            _h["npmD0"]->fill(p.pT()/GeV);
 54            _h["npmDplusD0sum"]->fill(p.pT()/GeV);
 55            if (p.pT() >= 2*GeV) _h_frag["npmDpD0"]->fill("PP --> D (Q=NON-PROMPT) + X"s);
 56          }
 57          else if (p.abspid() == PID::DPLUS) {
 58            _h["npmDplus"]->fill(p.pT()/GeV);
 59            _h["npmDplusD0sum"]->fill(p.pT()/GeV);
 60            if (p.pT() >= 2*GeV) _h_frag["npmDpD0"]->fill("PP --> D (Q=NON-PROMPT) + X"s);
 61          }
 62          else if (p.abspid() == PID::DSPLUS) {
 63            _h["npmDS"]->fill(p.pT()/GeV);
 64            if (p.pT() >= 2*GeV) _h_frag["npmDS"]->fill("PP --> D (Q=NON-PROMPT) + X"s);
 65          }
 66        }
 67        else {
 68          if (p.abspid() == PID::D0) {
 69            _h["pmD0"]->fill(p.pT()/GeV);
 70            _h["pmDplusD0sum"]->fill(p.pT()/GeV);
 71            if (p.pT() >= 1*GeV) _h_frag["pmDpD0"]->fill("PP --> D (Q=PROMPT) + X"s);
 72          }
 73          else if (p.abspid() == PID::DPLUS) {
 74            _h["pmDplus"]->fill(p.pT()/GeV);
 75            _h["pmDplusD0sum"]->fill(p.pT()/GeV);
 76            if (p.pT() >= 1*GeV) _h_frag["pmDpD0"]->fill("PP --> D (Q=PROMPT) + X"s);
 77          }
 78          else if (p.abspid() == PID::DSPLUS) {
 79            _h["pmDS"]->fill(p.pT()/GeV);
 80            if (p.pT() >= 1*GeV) _h_frag["pmDS"]->fill("PP --> D (Q=PROMPT) + X"s);
 81          }
 82        }
 83      }
 84    }
 85
 86    void finalize() {
 87
 88      const double sf = crossSection() / (microbarn*2*sumOfWeights());
 89      scale(_h, sf);
 90      scale(_h_frag, 0.5*sf);
 91
 92      for (auto& item : _e) {
 93        size_t delim = item.first.find("_");
 94        YODA::Histo1D num = *_h[item.first.substr(0, delim)];
 95        if (!item.second->binning().isCompatible(num.binning())) {
 96          num = num.clone();
 97          num.rebinXTo(item.second->xEdges());
 98        }
 99        YODA::Histo1D den = *_h[item.first.substr(delim+1)];
100        if (!item.second->binning().isCompatible(den.binning())) {
101          den = den.clone();
102          den.rebinXTo(item.second->xEdges());
103        }
104        divide(num, den, item.second);
105      }
106
107      for (auto& item : _e_frag) {
108        size_t delim = item.first.find("_");
109        divide(_h_frag[item.first.substr(0, delim)],
110               _h_frag[item.first.substr(delim+1)],
111               item.second);
112      }
113    }
114
115  private:
116
117    map<string, Histo1DPtr> _h;
118    map<string, BinnedHistoPtr<string>> _h_frag;
119
120    map<string, Estimate1DPtr> _e;
121    map<string, BinnedEstimatePtr<string>> _e_frag;
122
123  };
124
125  RIVET_DECLARE_PLUGIN(ALICE_2021_I1848990);
126
127}