Rivet analyses referenceLHCB_2013_I1218996Charm hadron differential cross-sections in p_\perp and rapidityExperiment: LHCB (LHC 7TeV) Inspire ID: 1218996 Status: VALIDATED Authors:
Beam energies: (3500.0, 3500.0) GeV Run details:
Measurements of differential production cross-sections with respect to transverse momentum, $d \sigma(H_c + \mathrm{c.c.}) / d p_T$, for charm hadron species $H_c \in \{ D^0, D^+, D^\ast(2010)^+, D_s^+, \Lambda_c^+ \}$ in proton--proton collisions at center-of-mass energy $\sqrt{s}= 7$ TeV. The differential cross-sections are measured in bins of hadron transverse momentum ($p_T$) and rapidity ($y$) with respect to the beam axis in the region $0 < p_T < 8$ GeV/$c$ and $2.0 < y < 4.5$, where $p_T$ and $y$ are measured in the proton--proton CM frame. In this analysis code, it is assumed that the event coordinate system is in the proton--proton CM frame with the $z$-axis corresponding to the proton--proton collision axis (as usual). Contributions of charm hadrons from the decays of $b$-hadrons and other particles with comparably large mean lifetimes have been removed in the measurement. In this analysis code, this is implemented by counting only charm hadrons that do not have an ancestor that contains a $b$ quark. Source code: LHCB_2013_I1218996.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4#include "Rivet/Projections/UnstableParticles.hh"
5
6namespace Rivet {
7
8
9 /// LHCb prompt charm hadron pT and rapidity spectra
10 class LHCB_2013_I1218996 : public Analysis {
11 public:
12
13 /// @name Constructors etc.
14 /// @{
15
16 /// Constructor
17 RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2013_I1218996);
18
19 /// @}
20
21
22 /// @name Analysis methods
23 /// @{
24
25 /// Book histograms and initialise projections before the run
26 void init() {
27
28 /// Initialise and register projections
29 declare(UnstableParticles(), "UFS");
30
31 /// Book histograms
32 book(_h_pdg421_Dzero_pT_y, {2., 2.5, 3., 3.5, 4., 4.5});
33 book(_h_pdg411_Dplus_pT_y, {2., 2.5, 3., 3.5, 4., 4.5});
34 book(_h_pdg413_Dstarplus_pT_y, {2., 2.5, 3., 3.5, 4., 4.5});
35 book(_h_pdg431_Dsplus_pT_y, {2., 2.5, 3., 3.5, 4., 4.5});
36 for (size_t i = 1; i < _h_pdg421_Dzero_pT_y->numBins()+1; ++i) {
37 size_t y = _h_pdg421_Dzero_pT_y->bin(i).index();
38 book(_h_pdg421_Dzero_pT_y->bin(i), 2, 1, y);
39 book(_h_pdg411_Dplus_pT_y->bin(i), 3, 1, y);
40 book(_h_pdg413_Dstarplus_pT_y->bin(i), 4, 1, y);
41 book(_h_pdg431_Dsplus_pT_y->bin(i), 5, 1, y);
42 }
43 book(_h_pdg4122_Lambdac_pT ,1, 1, 1);
44 }
45
46
47 /// Perform the per-event analysis
48 void analyze(const Event& event) {
49
50 /// @todo Use PrimaryHadrons to avoid double counting and automatically remove the contributions from unstable?
51 const UnstableParticles &ufs = apply<UnstableParticles> (event, "UFS");
52 for (const Particle& p : ufs.particles() ) {
53
54 // We're only interested in charm hadrons
55 if (!p.isHadron() || !p.hasCharm()) continue;
56
57 // Kinematic acceptance
58 const double y = p.absrap(); ///< Double analysis efficiency with a "two-sided LHCb"
59 const double pT = p.pT();
60
61 // Fiducial acceptance of the measurements
62 if (pT > 8.0*GeV || y < 2.0 || y > 4.5) continue;
63
64 /// Experimental selection removes non-prompt charm hadrons: we ignore those from b decays
65 if (p.fromBottom()) continue;
66
67 switch (p.abspid()) {
68 case 411:
69 _h_pdg411_Dplus_pT_y->fill(y, pT/GeV);
70 break;
71 case 421:
72 _h_pdg421_Dzero_pT_y->fill(y, pT/GeV);
73 break;
74 case 431:
75 _h_pdg431_Dsplus_pT_y->fill(y, pT/GeV);
76 break;
77 case 413:
78 _h_pdg413_Dstarplus_pT_y->fill(y, pT/GeV);
79 break;
80 case 4122:
81 _h_pdg4122_Lambdac_pT->fill(pT/GeV);
82 break;
83 }
84 }
85
86 }
87
88
89 /// Normalise histograms etc., after the run
90 void finalize() {
91 const double scale_factor = 0.5 * crossSection()/microbarn / sumOfWeights();
92 scale(_h_pdg411_Dplus_pT_y, scale_factor);
93 scale(_h_pdg421_Dzero_pT_y, scale_factor);
94 scale(_h_pdg431_Dsplus_pT_y, scale_factor);
95 scale(_h_pdg413_Dstarplus_pT_y, scale_factor);
96 _h_pdg4122_Lambdac_pT->scaleW(scale_factor);
97 }
98
99 /// @}
100
101
102 private:
103
104 /// @name Histograms
105 /// @{
106 Histo1DGroupPtr _h_pdg411_Dplus_pT_y;
107 Histo1DGroupPtr _h_pdg421_Dzero_pT_y;
108 Histo1DGroupPtr _h_pdg431_Dsplus_pT_y;
109 Histo1DGroupPtr _h_pdg413_Dstarplus_pT_y;
110 Histo1DPtr _h_pdg4122_Lambdac_pT;
111 /// @}
112
113
114 };
115
116
117 RIVET_DECLARE_PLUGIN(LHCB_2013_I1218996);
118
119}
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