Rivet analyses referenceZEUS_2008_I810112Measurement of $D^{\pm}$ and $D^0$ production in deep inelastic scattering using a lifetime tag at HERAExperiment: ZEUS (HERA) Inspire ID: 810112 Status: VALIDATED Authors:
Beam energies: ANY Run details:
The production of $D^{\pm}$ and $D^{0}$ mesons has been measured with the ZEUS detector at HERA using an integrated luminosity of $133.6 pb^{-1}$. The measurements cover the kinematic range $5 < Q^2 < 1000 GeV^2$, $0.02 < y < 0.7$, $1.5 < p_T^D < 15 GeV$ and $\eta^D < 1.6$. Combinatorial background to the D meson signals is reduced by using the ZEUS microvertex detector to reconstruct displaced secondary vertices. Production cross sections are compared with the predictions of next-to-leading-order QCD which is found to describe the data well. Measurements are extrapolated to the full kinematic phase space in order to obtain the open-charm contribution, $F_2^c\bar{c}$, to the proton structure function, $F_2$. Source code: ZEUS_2008_I810112.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/UnstableParticles.hh"
4#include "Rivet/Projections/FinalState.hh"
5#include "Rivet/Projections/FastJets.hh"
6#include "Rivet/Projections/DISFinalState.hh"
7
8namespace Rivet {
9
10
11 /// @brief Measurement of $D^{\pm}$ and $D^0$ production in deep inelastic scattering using a lifetime tag at HERA
12 ///
13 /// @author Andrii Verbytskyi
14 class ZEUS_2008_I810112 : public Analysis {
15 public:
16
17 /// Constructor
18 RIVET_DEFAULT_ANALYSIS_CTOR(ZEUS_2008_I810112);
19
20 /// @name Analysis methods
21 /// @{
22
23 /// Book histograms and initialise projections before the run
24 void init() {
25 /// Initialise and register projections
26 FinalState fs;
27 const DISKinematics& diskin = DISKinematics();
28 declare(diskin,"Kinematics");
29 declare(UnstableParticles(), "UPS");
30
31 book(_h_Dp_q2, 3, 1, 1);
32 book(_h_Dp_x, 4, 1, 1);
33 book(_h_Dp_pt, 5, 1, 1);
34 book(_h_Dp_eta, 6, 1, 1);
35
36 book(_h_Dp_yinq2[0], "TMP/Dp0", refData( 11, 1, 1));
37 book(_h_Dp_yinq2[1], "TMP/Dp1", refData( 11, 1, 2));
38 book(_h_Dp_yinq2[2], "TMP/Dp2", refData( 11, 1, 3));
39
40 book(_s_Dp_yinq2[0], 11, 1, 1);
41 book(_s_Dp_yinq2[1], 11, 1, 2);
42 book(_s_Dp_yinq2[2], 11, 1, 3);
43
44 book(_h_D0_q2, 7, 1, 1);
45 book(_h_D0_x, 8, 1, 1);
46 book(_h_D0_pt, 9, 1, 1);
47 book(_h_D0_eta, 10, 1, 1);
48
49 book(_h_D0_yinq2[0], "TMP/D00", refData( 12, 1, 1));
50 book(_h_D0_yinq2[1], "TMP/D01", refData( 12, 1, 2));
51 book(_h_D0_yinq2[2], "TMP/D02", refData( 12, 1, 3));
52
53 book(_s_D0_yinq2[0], 12, 1, 1);
54 book(_s_D0_yinq2[1], 12, 1, 2);
55 book(_s_D0_yinq2[2], 12, 1, 3);
56 }
57
58
59 /// A routine that selects the bin in kinematic space
60 int _getbinQ2_OK(const DISKinematics& dk) {
61 if (inRange(dk.Q2()/GeV2, 5.0, 9.0)) return 0;
62 if (inRange(dk.Q2()/GeV2, 9.0, 44.0)) return 1;
63 if (inRange(dk.Q2()/GeV2, 44.0, 1000.0)) return 2;
64 return -1;
65 }
66
67
68 /// Perform the per-event analysis
69 void analyze(const Event& event) {
70 /// DIS kinematics
71 const DISKinematics& dk = apply<DISKinematics>(event, "Kinematics");
72 double q2 = dk.Q2();
73 double x = dk.x();
74 double y = dk.y();
75
76 ///Assure the event falls into the kinematic range of the measurement.
77 if (!inRange(q2/GeV2, 5, 1000)) vetoEvent;
78 if (!inRange(y, 0.02, 0.7)) vetoEvent;
79
80 /// Find out in which bin the measurement falls.
81 int bin = _getbinQ2_OK(dk);
82 if ( bin < 0 ) vetoEvent;
83
84 const UnstableParticles& ufs = apply<UnstableParticles>(event, "UPS");
85
86 /// Get \f$D^0$\f particles
87 for (const Particle& p : select(ufs.particles(), Cuts::abspid == PID::D0)) {
88 ///But not not from \f$D^{*\pm}$\f decays
89 if (p.hasAncestorWith(Cuts::pid == PID::DSTARPLUS)) continue;
90 if (p.hasAncestorWith(Cuts::pid == PID::DSTARMINUS)) continue;
91 /// Select particles only in the \f$\eta-p_{T}$\f region
92 if (!inRange(p.eta(), -1.6, 1.6)) continue;
93 if (!inRange(p.pt()/GeV, 1.5, 15.0)) continue;
94 /// Fill the general histograms
95 _h_D0_pt->fill(p.pt()/GeV);
96 _h_D0_eta->fill(p.eta());
97 _h_D0_q2->fill(q2/GeV2);
98 _h_D0_x->fill(x);
99 /// Fill the cross-sections in selected kinematic bins
100 _h_D0_yinq2[bin]->fill(y);
101 }
102
103 /// Get \f$D^{\pm}$\f particles
104 for (const Particle& p : select(ufs.particles(), Cuts::abspid == PID::DPLUS)) {
105 /// Select particles only in the \f$\eta-p_{T}$\f region
106 if (!inRange(p.eta(), -1.6, 1.6)) continue;
107 if (!inRange(p.pt()/GeV, 1.5, 15.0)) continue;
108 /// Fill the general histograms
109 _h_Dp_pt->fill(p.pt()/GeV);
110 _h_Dp_eta->fill(p.eta());
111 _h_Dp_q2->fill(q2/GeV2);
112 _h_Dp_x->fill(x);
113 /// Fill the cross-sections in selected kinematic bins
114 _h_Dp_yinq2[bin]->fill(y);
115 }
116 }
117
118
119 /// Normalise histograms etc., after the run
120 void finalize() {
121 const double sf = crossSection()/nanobarn/sumOfWeights();
122 /// For CS comparison the MC should be corrected to difference between BR used for data and in MC
123 scale(_h_Dp_pt, sf);
124 scale(_h_Dp_eta, sf);
125 scale(_h_Dp_q2, sf);
126 scale(_h_Dp_x, sf);
127
128 for (size_t i = 0; i < 3; i++) {
129 scale(_h_Dp_yinq2[i], sf);
130 barchart(_h_Dp_yinq2[i], _s_Dp_yinq2[i]);
131 }
132
133 scale(_h_D0_pt, sf);
134 scale(_h_D0_eta, sf);
135 scale(_h_D0_q2, sf);
136 scale(_h_D0_x, sf);
137
138 for (size_t i = 0; i < 3; i++) {
139 scale(_h_D0_yinq2[i], sf);
140 barchart(_h_D0_yinq2[i], _s_D0_yinq2[i]);
141 }
142 }
143
144 /// @}
145
146
147 private:
148
149 Histo1DPtr _h_D0_pt, _h_D0_eta, _h_D0_q2, _h_D0_x, _h_D0_yinq2[3];
150 Histo1DPtr _h_Dp_pt, _h_Dp_eta, _h_Dp_q2, _h_Dp_x, _h_Dp_yinq2[3];
151
152 Estimate1DPtr _s_Dp_yinq2[3];
153 Estimate1DPtr _s_D0_yinq2[3];
154
155 };
156
157
158 RIVET_DECLARE_PLUGIN(ZEUS_2008_I810112);
159
160}
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