Rivet analyses referenceCMS_2011_I884811Production cross-sections of muons from $b$ hadron decays in $pp$ collisionsExperiment: CMS (LHC) Inspire ID: 884811 Status: VALIDATED Authors:
Beam energies: (3500.0, 3500.0) GeV Run details:
A measurement of the $b$-hadron production cross-section in proton-proton collisions at $\sqrt{s} = 7$ TeV. The dataset, corresponding to 85 inverse nanobarns, was recorded with the CMS experiment at the LHC using a low-threshold single-muon trigger. Events are selected by the presence of a muon with transverse momentum greater than 6 GeV with respect to the beam direction and pseudorapidity less than 2.1. The transverse momentum of the muon with respect to the closest jet discriminates events containing $b$ hadrons from background. The inclusive $b$-hadron production cross section is presented as a function of muon transverse momentum and pseudorapidity. Source code: CMS_2011_I884811.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/IdentifiedFinalState.hh"
4#include "Rivet/Particle.hh"
5
6namespace Rivet {
7
8
9 /// Production cross-sections of muons from $b$ hadron decays in $pp$ collisions
10 class CMS_2011_I884811 : public Analysis {
11 public:
12
13 RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2011_I884811);
14
15
16 /// Book histograms and initialise projections before the run
17 void init() {
18 book(_h_total ,1, 1, 1);
19 book(_h_mupt ,2, 1, 1);
20 book(_h_mueta ,3, 1, 1);
21
22 IdentifiedFinalState ifs(Cuts::abseta < 2.1 && Cuts::pT > 6*GeV);
23 ifs.acceptIdPair(PID::MUON);
24 declare(ifs, "IFS");
25 }
26
27
28 /// Perform the per-event analysis
29 void analyze(const Event& event) {
30
31 // a b-quark must have been produced
32 /// @todo Ouch. Use hadron tagging...
33 int nb = 0;
34 for(ConstGenParticlePtr p: HepMCUtils::particles(event.genEvent())) {
35 if (abs(p->pdg_id()) == PID::BQUARK) nb += 1;
36 }
37 if (nb == 0) vetoEvent;
38
39 // Event must contain a muon
40 Particles muons = apply<IdentifiedFinalState>(event, "IFS").particlesByPt();
41 if (muons.size() < 1) vetoEvent;
42
43 FourMomentum pmu = muons[0].momentum();
44 _h_total->fill(7000);
45 _h_mupt->fill(pmu.pT()/GeV);
46 _h_mueta->fill(pmu.eta()/GeV);
47 }
48
49
50 /// Normalise histograms etc., after the run
51 void finalize() {
52 scale(_h_total, crossSection()/microbarn/sumOfWeights());
53 scale(_h_mupt, crossSection()/nanobarn/sumOfWeights());
54 scale(_h_mueta, crossSection()/nanobarn/sumOfWeights());
55 }
56
57
58 private:
59
60 /// @{
61 BinnedHistoPtr<int> _h_total;
62 Histo1DPtr _h_mupt;
63 Histo1DPtr _h_mueta;
64 /// @}
65
66 };
67
68
69
70 RIVET_DECLARE_ALIASED_PLUGIN(CMS_2011_I884811, CMS_2011_S8941262);
71
72}
|
