Rivet analyses referenceCMS_2011_I889807$B/\bar{B}$ angular correlations based on secondary vertex reconstruction in $pp$ collisionsExperiment: CMS (LHC) Inspire ID: 889807 Status: VALIDATED Authors:
Beam energies: (3500.0, 3500.0) GeV Run details:
The differential $B\bar{B}$ cross-section is measured as a function of the opening angle $\Delta{R}$ and $\Delta\phi$ using data collected with the CMS detector during 2010 and corresponding to an integrated luminosity of 3.1 pb$^{-1}$. The measurement is performed for three different event energy scales, characterized by the transverse momentum of the leading jet in the event (above 56 GeV, above 84 GeV and above 120 GeV). Simulated events are normalised in the region $\Delta{R} > 2.4$ and $\Delta\phi > 3/4\pi$ respectively. Source code: CMS_2011_I889807.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4#include "Rivet/Projections/UnstableParticles.hh"
5#include "Rivet/Projections/FastJets.hh"
6
7namespace Rivet {
8
9
10 /// B-Bbar angular correlations based on secondary vertex reconstruction
11 class CMS_2011_I889807 : public Analysis {
12 public:
13
14 RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2011_I889807);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 void init() {
21 FinalState fs;
22 FastJets jetproj(fs, JetAlg::ANTIKT, 0.5);
23 jetproj.useInvisibles();
24 declare(jetproj, "Jets");
25
26 UnstableParticles ufs;
27 declare(ufs, "UFS");
28
29 // Book histograms
30 book(_h_dsigma_dR_56GeV ,1,1,1);
31 book(_h_dsigma_dR_84GeV ,2,1,1);
32 book(_h_dsigma_dR_120GeV ,3,1,1);
33 book(_h_dsigma_dPhi_56GeV ,4,1,1);
34 book(_h_dsigma_dPhi_84GeV ,5,1,1);
35 book(_h_dsigma_dPhi_120GeV ,6,1,1);
36
37 book(_c["MCDR56"], "_MCDR56");
38 book(_c["MCDR84"], "_MCDR84");
39 book(_c["MCDR120"], "_MCDR120");
40 book(_c["MCDPhi56"], "_MCDPhi56");
41 book(_c["MCDPhi84"], "_MCDPhi84");
42 book(_c["MCDPhi120"], "_MCDPhi120");
43 }
44
45
46 /// Perform the per-event analysis
47 void analyze(const Event& event) {
48
49 const Jets& jets = apply<FastJets>(event,"Jets").jetsByPt();
50 const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
51
52 // Find the leading jet pT and eta
53 if (jets.size() == 0) vetoEvent;
54 const double ljpT = jets[0].pT();
55 const double ljeta = jets[0].eta();
56 MSG_DEBUG("Leading jet pT / eta: " << ljpT << " / " << ljeta);
57
58 // Minimum requirement for event
59 if (ljpT > 56*GeV && fabs(ljeta) < 3.0) {
60 // Find B hadrons in event
61 int nb = 0; //counters for all B and independent B hadrons
62 double etaB1 = 7.7, etaB2 = 7.7;
63 double phiB1 = 7.7, phiB2 = 7.7;
64 double pTB1 = 7.7, pTB2 = 7.7;
65
66 for (const Particle& p : ufs.particles()) {
67 int aid = p.abspid();
68 if (aid/100 == 5 || aid/1000==5) {
69 // 2J+1 == 1 (mesons) or 2 (baryons)
70 if (aid%10 == 1 || aid%10 == 2) {
71 // No B decaying to B
72 if (aid != 5222 && aid != 5112 && aid != 5212 && aid != 5322) {
73 if (nb==0) {
74 etaB1 = p.eta();
75 phiB1 = p.phi();
76 pTB1 = p.pT();
77 } else if (nb==1) {
78 etaB2 = p.eta();
79 phiB2 = p.phi();
80 pTB2 = p.pT();
81 }
82 nb++;
83 }
84 }
85 MSG_DEBUG("ID " << aid << " B hadron");
86 }
87 }
88
89 if (nb==2 && pTB1 > 15*GeV && pTB2 > 15*GeV && fabs(etaB1) < 2.0 && fabs(etaB2) < 2.0) {
90 double dPhi = deltaPhi(phiB1, phiB2);
91 double dR = deltaR(etaB1, phiB1, etaB2, phiB2);
92 MSG_DEBUG("DR/DPhi " << dR << " " << dPhi);
93
94 // MC counters
95 if (dR > 2.4) _c["MCDR56"]->fill();
96 if (dR > 2.4 && ljpT > 84*GeV) _c["MCDR84"]->fill();
97 if (dR > 2.4 && ljpT > 120*GeV) _c["MCDR120"]->fill();
98 if (dPhi > 3.*PI/4.) _c["MCDPhi56"]->fill();
99 if (dPhi > 3.*PI/4. && ljpT > 84*GeV) _c["MCDPhi84"]->fill();
100 if (dPhi > 3.*PI/4. && ljpT > 120*GeV) _c["MCDPhi120"]->fill();
101
102 _h_dsigma_dR_56GeV->fill(dR);
103 if (ljpT > 84*GeV) _h_dsigma_dR_84GeV->fill(dR);
104 if (ljpT > 120*GeV) _h_dsigma_dR_120GeV->fill(discEdge(dR));
105 _h_dsigma_dPhi_56GeV->fill(dPhi);
106 if (ljpT > 84*GeV) _h_dsigma_dPhi_84GeV->fill(dPhi);
107 if (ljpT > 120*GeV) _h_dsigma_dPhi_120GeV->fill(dPhi);
108 }
109 }
110 }
111
112
113 /// Normalise histograms etc., after the run
114 void finalize() {
115 MSG_DEBUG("crossSection " << crossSection()/picobarn << " sumOfWeights " << sumOfWeights());
116
117 // Hardcoded bin widths
118 double DRbin = 0.4;
119 double DPhibin = PI/8.0;
120 // Find out the correct numbers
121 double nDataDR56 = 25862.20;
122 double nDataDR84 = 5675.55;
123 double nDataDR120 = 1042.72;
124 double nDataDPhi56 = 24220.00;
125 double nDataDPhi84 = 4964.00;
126 double nDataDPhi120 = 919.10;
127 double normDR56 = safediv(nDataDR56, dbl(*_c["MCDR56"]), crossSection()/picobarn/sumOfWeights());
128 double normDR84 = safediv(nDataDR84, dbl(*_c["MCDR84"]), crossSection()/picobarn/sumOfWeights());
129 double normDR120 = safediv(nDataDR120, dbl(*_c["MCDR120"]), crossSection()/picobarn/sumOfWeights());
130 double normDPhi56 = safediv(nDataDPhi56, dbl(*_c["MCDPhi56"]), crossSection()/picobarn/sumOfWeights());
131 double normDPhi84 = safediv(nDataDPhi84, dbl(*_c["MCDPhi84"]), crossSection()/picobarn/sumOfWeights());
132 double normDPhi120 = safediv(nDataDPhi120, dbl(*_c["MCDPhi120"]), crossSection()/picobarn/sumOfWeights());
133 scale(_h_dsigma_dR_56GeV, normDR56*DRbin);
134 scale(_h_dsigma_dR_84GeV, normDR84*DRbin);
135 scale(_h_dsigma_dR_120GeV, normDR120*DRbin);
136 scale(_h_dsigma_dPhi_56GeV, normDPhi56*DPhibin);
137 scale(_h_dsigma_dPhi_84GeV, normDPhi84*DPhibin);
138 scale(_h_dsigma_dPhi_120GeV, normDPhi120*DPhibin);
139 for (auto& b : _h_dsigma_dR_120GeV->bins()) {
140 b.scaleW(1.0/_rapaxis.width(b.index()));
141 }
142 }
143
144 string discEdge(const double value) const {
145 const size_t idx = _rapaxis.index(value);
146 return _h_dsigma_dR_120GeV->bin(idx).xEdge();
147 }
148
149 /// @}
150
151
152 private:
153
154 /// Counters
155 map<string, CounterPtr> _c;
156
157 /// @name Histograms
158 /// @{
159 Histo1DPtr _h_dsigma_dR_56GeV, _h_dsigma_dR_84GeV;
160 BinnedHistoPtr<string> _h_dsigma_dR_120GeV; // Why does this one have a different type?
161 Histo1DPtr _h_dsigma_dPhi_56GeV, _h_dsigma_dPhi_84GeV, _h_dsigma_dPhi_120GeV;
162 YODA::Axis<double> _rapaxis{ 0.0, 0.4, 0.8, 1.2, 1.6, 2.0, 2.4, 2.8, 3.2, 3.6, 4.0 };
163 /// @}
164
165 };
166
167
168
169 RIVET_DECLARE_ALIASED_PLUGIN(CMS_2011_I889807, CMS_2011_S8973270);
170
171}
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