Rivet analyses referenceALICE_2022_I1868463$\Sigma_c^{0,+,++}$ and $\Lambda_c$ from $\Sigma_c^{0,+,++}$ analysisExperiment: ALICE (LHC) Inspire ID: 1868463 Status: VALIDATED Authors:
Beam energies: (6500.0, 6500.0) GeV Run details:
The $p_\mathrm{T}$-differential production cross sections of prompt ${\rm D^{0}}$, ${\rm \Lambda_{c}^{+}}$, and ${\rm \Sigma_{c}^{0,++}}(2455)$ charmed hadrons are measured at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}=13$ TeV. This is the first measurement of ${\rm \Sigma_{c}^{0,++}}$ production in hadronic collisions. Assuming the same production yield for the three $\rm \Sigma_{c}^{0,+,++}$ isospin states, the baryon-to-meson cross section ratios $\rm \Sigma_{c}^{0,+,++}/\rm D^{0}$ and $\rm \Lambda_{c}^{+}/\rm D^{0}$ are calculated in the transverse momentum ($p_{\rm T}$) intervals $2<p_{\rm T}<12$ GeV/$c$ and $1<p_{\rm T}<24$ GeV/$c$. Values significantly larger than in $\rm e^{+}e^{-}$ collisions are observed, indicating for the first time that baryon enhancement in hadronic collisions also extends to the $\mathrm{\Sigma_{c}}$. The feed-down contribution to $\rm \Lambda_{c}^{+}$ production from $\rm \Sigma_{c}^{0,+,++}$ is also reported and is found to be larger than in $\rm e^{+}e^{-}$ collisions. The data are compared with predictions from event generators and other phenomenological models, providing a sensitive test of the different charm-hadronisation mechanisms implemented in the models. Source code: ALICE_2022_I1868463.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/UnstableParticles.hh"
4
5
6namespace Rivet {
7
8
9 /// @brief Measurement of prompt charm hadrons production in proton-proton Collisions at 13 TeV
10 class ALICE_2022_I1868463 : public Analysis {
11 public:
12
13 /// Constructor
14 RIVET_DEFAULT_ANALYSIS_CTOR(ALICE_2022_I1868463);
15
16
17 /// @name Analysis methods
18 ///@{
19
20 /// Book histograms and initialise projections before the run
21 void init() {
22
23 // Initialise and register projections
24
25 // The basic final-state projection:
26 // all final-state particles within
27 // the given eta acceptance
28 const UnstableParticles up(Cuts::absrap < 0.5);
29 declare(up, "up");
30
31 book(_h_D0,1,1,1);
32 book(_h_Lc,2,1,1);
33 book(_h_Sc,3,1,1);
34 book(_h_LcfromSc,4,1,1);
35 book(_h_LcD0,5,1,1);
36 book(_h_ScD0,6,1,1);
37 book(_h_LcfromScLc,7,1,1);
38 book(_h_D04Sc,"TMP/D04Sc",refData(3,1,1));
39 book(_h_Lc4Ratio, "TMP/Lc4Ratio", refData(4,1,1));
40
41 }
42
43
44 /// Perform the per-event analysis
45 void analyze(const Event& event) {
46
47 const UnstableParticles& up = apply<UnstableParticles>(event, "up");
48
49 for (const Particle& p : up.particles()) {
50 if(p.fromBottom())
51 continue;
52 else{
53 if(p.abspid()==4222 || p.abspid()==4212 || p.abspid()==4112)
54 _h_Sc->fill(p.pT()/GeV);
55 else if(p.abspid()==4122){
56 _h_Lc->fill(p.pT()/GeV);
57 _h_Lc4Ratio->fill(p.pT()/GeV);
58 if(p.hasAncestor(4222) || p.hasAncestor(4212) || p.hasAncestor(4112) || p.hasAncestor(-4222) || p.hasAncestor(-4212) || p.hasAncestor(-4112))
59 _h_LcfromSc->fill(p.pT()/GeV);
60 }
61 else if(p.abspid()==421){
62 _h_D0->fill(p.pT()/GeV);
63 _h_D04Sc->fill(p.pT()/GeV);
64 }
65 }
66 }
67 }
68
69
70 /// Normalise histograms etc., after the run
71 void finalize() {
72
73 scale(_h_D0, crossSection()/(microbarn*2*sumOfWeights()));
74 scale(_h_Lc, crossSection()/(microbarn*2*sumOfWeights()));
75 scale(_h_LcfromSc, crossSection()/(microbarn*2*sumOfWeights()));
76 scale(_h_Lc4Ratio, crossSection()/(microbarn*2*sumOfWeights()));
77 scale(_h_Sc, crossSection()/(microbarn*2*sumOfWeights()));
78 scale(_h_D04Sc, crossSection()/(microbarn*2*sumOfWeights())); // norm to generated cross-section in pb (after cuts)
79 divide(_h_Sc, _h_D04Sc, _h_ScD0);
80 divide(_h_Lc, _h_D0, _h_LcD0);
81 divide(_h_LcfromSc, _h_Lc4Ratio, _h_LcfromScLc);
82
83 }
84
85 ///@}
86
87
88 /// @name Histograms
89 ///@{
90 Histo1DPtr _h_Sc, _h_D0, _h_D04Sc, _h_LcfromSc, _h_Lc , _h_Lc4Ratio;
91 Scatter2DPtr _h_LcD0, _h_ScD0, _h_LcfromScLc;
92 ///@}
93
94
95 };
96
97
98 RIVET_DECLARE_PLUGIN(ALICE_2022_I1868463);
99
100}
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