Rivet analyses referenceCMS_2011_S8973270$B/\bar{B}$ 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_S8973270.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_S8973270 : public Analysis {
12 public:
13
14 RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2011_S8973270);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 void init() {
21 FinalState fs;
22 FastJets jetproj(fs, FastJets::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 const double weight = 1.0;
49
50 const Jets& jets = apply<FastJets>(event,"Jets").jetsByPt();
51 const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
52
53 // Find the leading jet pT and eta
54 if (jets.size() == 0) vetoEvent;
55 const double ljpT = jets[0].pT();
56 const double ljeta = jets[0].eta();
57 MSG_DEBUG("Leading jet pT / eta: " << ljpT << " / " << ljeta);
58
59 // Minimum requirement for event
60 if (ljpT > 56*GeV && fabs(ljeta) < 3.0) {
61 // Find B hadrons in event
62 int nab = 0, nb = 0; //counters for all B and independent B hadrons
63 double etaB1 = 7.7, etaB2 = 7.7;
64 double phiB1 = 7.7, phiB2 = 7.7;
65 double pTB1 = 7.7, pTB2 = 7.7;
66
67 for (const Particle& p : ufs.particles()) {
68 int aid = p.abspid();
69 if (aid/100 == 5 || aid/1000==5) {
70 nab++;
71 // 2J+1 == 1 (mesons) or 2 (baryons)
72 if (aid%10 == 1 || aid%10 == 2) {
73 // No B decaying to B
74 if (aid != 5222 && aid != 5112 && aid != 5212 && aid != 5322) {
75 if (nb==0) {
76 etaB1 = p.eta();
77 phiB1 = p.phi();
78 pTB1 = p.pT();
79 } else if (nb==1) {
80 etaB2 = p.eta();
81 phiB2 = p.phi();
82 pTB2 = p.pT();
83 }
84 nb++;
85 }
86 }
87 MSG_DEBUG("ID " << aid << " B hadron");
88 }
89 }
90
91 if (nb==2 && pTB1 > 15*GeV && pTB2 > 15*GeV && fabs(etaB1) < 2.0 && fabs(etaB2) < 2.0) {
92 double dPhi = deltaPhi(phiB1, phiB2);
93 double dR = deltaR(etaB1, phiB1, etaB2, phiB2);
94 MSG_DEBUG("DR/DPhi " << dR << " " << dPhi);
95
96 // MC counters
97 if (dR > 2.4) _c["MCDR56"]->fill();
98 if (dR > 2.4 && ljpT > 84*GeV) _c["MCDR84"]->fill();
99 if (dR > 2.4 && ljpT > 120*GeV) _c["MCDR120"]->fill();
100 if (dPhi > 3.*PI/4.) _c["MCDPhi56"]->fill();
101 if (dPhi > 3.*PI/4. && ljpT > 84*GeV) _c["MCDPhi84"]->fill();
102 if (dPhi > 3.*PI/4. && ljpT > 120*GeV) _c["MCDPhi120"]->fill();
103
104 _h_dsigma_dR_56GeV->fill(dR, weight);
105 if (ljpT > 84*GeV) _h_dsigma_dR_84GeV->fill(dR, weight);
106 if (ljpT > 120*GeV) _h_dsigma_dR_120GeV->fill(dR, weight);
107 _h_dsigma_dPhi_56GeV->fill(dPhi, weight);
108 if (ljpT > 84*GeV) _h_dsigma_dPhi_84GeV->fill(dPhi, weight);
109 if (ljpT > 120*GeV) _h_dsigma_dPhi_120GeV->fill(dPhi, weight);
110 //MSG_DEBUG("nb " << nb << " " << nab);
111 }
112 }
113 }
114
115
116 /// Normalise histograms etc., after the run
117 void finalize() {
118 MSG_DEBUG("crossSection " << crossSection() << " sumOfWeights " << sumOfWeights());
119
120 // Hardcoded bin widths
121 double DRbin = 0.4;
122 double DPhibin = PI/8.0;
123 // Find out the correct numbers
124 double nDataDR56 = 25862.20;
125 double nDataDR84 = 5675.55;
126 double nDataDR120 = 1042.72;
127 double nDataDPhi56 = 24220.00;
128 double nDataDPhi84 = 4964.00;
129 double nDataDPhi120 = 919.10;
130 double normDR56 = safediv(nDataDR56, dbl(*_c["MCDR56"]), crossSection()/sumOfWeights());
131 double normDR84 = safediv(nDataDR84, dbl(*_c["MCDR84"]), crossSection()/sumOfWeights());
132 double normDR120 = safediv(nDataDR120, dbl(*_c["MCDR120"]), crossSection()/sumOfWeights());
133 double normDPhi56 = safediv(nDataDPhi56, dbl(*_c["MCDPhi56"]), crossSection()/sumOfWeights());
134 double normDPhi84 = safediv(nDataDPhi84, dbl(*_c["MCDPhi84"]), crossSection()/sumOfWeights());
135 double normDPhi120 = safediv(nDataDPhi120, dbl(*_c["MCDPhi120"]), crossSection()/sumOfWeights());
136 scale(_h_dsigma_dR_56GeV, normDR56*DRbin);
137 scale(_h_dsigma_dR_84GeV, normDR84*DRbin);
138 scale(_h_dsigma_dR_120GeV, normDR120*DRbin);
139 scale(_h_dsigma_dPhi_56GeV, normDPhi56*DPhibin);
140 scale(_h_dsigma_dPhi_84GeV, normDPhi84*DPhibin);
141 scale(_h_dsigma_dPhi_120GeV, normDPhi120*DPhibin);
142 }
143
144 /// @}
145
146
147 private:
148
149 /// Counters
150 map<string, CounterPtr> _c;
151
152 /// @name Histograms
153 /// @{
154 Histo1DPtr _h_dsigma_dR_56GeV, _h_dsigma_dR_84GeV, _h_dsigma_dR_120GeV;
155 Histo1DPtr _h_dsigma_dPhi_56GeV, _h_dsigma_dPhi_84GeV, _h_dsigma_dPhi_120GeV;
156 /// @}
157
158 };
159
160
161
162 RIVET_DECLARE_ALIASED_PLUGIN(CMS_2011_S8973270, CMS_2011_I889807);
163
164}
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