|
|
Rivet analyses reference
D0_2000_I499943
The $b\bar{b}$ production cross-section and angular correlations
Experiment: D0 (Tevatron Run 1)
Inspire ID: 499943
Status: VALIDATED
Authors:
References:
Beams: p- p+
Beam energies: (900.0, 900.0) GeV
Run details:
- $p\bar{p}$ dijet events at 1.8\;\text{TeV}, with a minimum \pt of 12\;GeV.
Measurements of the $b\bar{b}$ production cross-section and angular correlations using the D0 detector at the Fermilab Tevatron $p\bar{p}$ collider operating at $\sqrt{s} = 1.8\;\text{TeV}$. The $b$ quark production cross-section and the angular correlations between $b$-quark pairs, for $|y(b)| < 1.0$ and $p_T(b) > 6\;\text{GeV}/c$, are extracted from single muon and dimuon data samples.
Source code:
D0_2000_I499943.cc
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/HeavyHadrons.hh"
#include "Rivet/Projections/IdentifiedFinalState.hh"
namespace Rivet {
class D0_2000_I499943 : public Analysis {
public:
/// Constructor
D0_2000_I499943()
: Analysis("D0_2000_I499943")
{ }
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
FinalState fs;
IdentifiedFinalState muons(Cuts::abseta < 0.8 && Cuts::pT > 4.0*GeV);
muons.acceptIdPair(PID::MUON);
declare(muons, "Muons");
FastJets jetproj(fs, FastJets::D0ILCONE, 0.7);
jetproj.useInvisibles();
declare(jetproj, "Jets");
// Book histograms
book(_h_pt_leading_mu ,1, 1, 1);
book(_h_dphi_mumu ,3, 1, 1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
const Jets& jets = apply<FastJets>(event, "Jets").jetsByPt(12*GeV);
if (jets.size() < 2) vetoEvent;
const Particles& muons = apply<IdentifiedFinalState>(event, "Muons").particlesByPt();
if (muons.size() < 2) vetoEvent;
// Muon selection: require the muons to be *close* to jets, not the usual overlap vetoing!
Particles cand_mu;
for (const Particle& mu : muons) {
// Ignore muons in "bad" region 80 < phi < 110 degrees
/// @todo Is this really not corrected for?!
if (inRange(mu.phi(), 1.4, 1.92)) continue;
// A muon is a good candidate if within R = 0.8 of a jet
for (const Jet& jet : jets) {
if (deltaR(mu, jet) < 0.8) {
cand_mu.push_back(mu);
break;
}
}
}
// Must find at least two jet-matched muons in the event
if (cand_mu.size() < 2) vetoEvent;
/// @todo Is this cut needed? Does space angle mean dR or 3D opening angle in lab frame?
// Remove muon pairs closer than 165 deg in space angle (cosmic veto)
// double dR_mumu = deltaR(cand_mu[0].momentum(), cand_mu[1].momentum());
// if (dR_mumu < 165*degree) vetoEvent;
// Selecting muon pairs with 6 < mass < 35 GeV (we use the two with highest pT)
double m_mumu = (cand_mu[0].momentum() + cand_mu[1].momentum()).mass();
if (!inRange(m_mumu, 6*GeV, 35*GeV)) vetoEvent;
// Get phi angle between muons in degrees
double dphi_mumu = deltaPhi(cand_mu[0], cand_mu[1]) * 180/M_PI;
// Fill histos
_h_pt_leading_mu->fill(cand_mu[0].pt()/GeV);
_h_dphi_mumu->fill(dphi_mumu);
}
// Normalise histograms to cross-section
void finalize() {
scale(_h_pt_leading_mu, crossSection()/sumOfWeights()/nanobarn);
scale(_h_dphi_mumu, crossSection()/sumOfWeights()/nanobarn);
}
//@}
private:
/// @name Histograms
//@{
Histo1DPtr _h_pt_leading_mu, _h_dphi_mumu;
//@}
};
// The hook for the plugin system
DECLARE_RIVET_PLUGIN(D0_2000_I499943);
}
|
|