Rivet analyses referenceALEPH_1991_I319520Hadronic Z decay charged multiplicity measurementExperiment: ALEPH (LEP 1) Inspire ID: 319520 Status: VALIDATED Authors:
Beam energies: (45.6, 45.6) GeV Run details:
The charged particle multiplicity distribution of hadronic Z decays, as measured on the peak of the Z resonance using the ALEPH detector at LEP. The unfolding procedure was model independent, and the distribution was found to have a mean of $20.85 \pm 0.24$, Comparison with lower energy data supports the KNO scaling hypothesis. The shape of the multiplicity distribution is well described by a log-normal distribution, as predicted from a cascading model for multi-particle production. Source code: ALEPH_1991_I319520.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/ChargedFinalState.hh"
4
5namespace Rivet {
6
7
8 /// @brief ALEPH LEP1 charged multiplicity in hadronic Z decay
9 ///
10 /// @author Andy Buckley
11 class ALEPH_1991_I319520 : public Analysis {
12 public:
13
14 RIVET_DEFAULT_ANALYSIS_CTOR(ALEPH_1991_I319520);
15
16
17 /// @name Analysis methods
18 /// @{
19
20 /// Book projections and histogram
21 void init() {
22 const ChargedFinalState cfs;
23 declare(cfs, "CFS");
24
25 book(_histChTot ,1, 1, 1);
26 book(_histAver, 2, 1, 1);
27 }
28
29
30 /// Do the analysis
31 void analyze(const Event& event) {
32 const FinalState& cfs = apply<FinalState>(event, "CFS");
33 MSG_DEBUG("Total charged multiplicity = " << cfs.size());
34 _histChTot->fill(cfs.size());
35 _histAver->fill(Ecms, cfs.size());
36 }
37
38
39 /// Normalize the histogram
40 void finalize() {
41 scale(_histChTot, 1./sumOfWeights()); // same as in ALEPH 1996
42 scale(_histAver , 1./sumOfWeights());
43 }
44
45 /// @}
46
47
48 /// @name Histograms
49 /// @{
50 BinnedHistoPtr<int> _histChTot;
51 BinnedHistoPtr<string> _histAver;
52 const string Ecms = "91.25";
53 /// @}
54
55 };
56
57
58
59 RIVET_DECLARE_ALIASED_PLUGIN(ALEPH_1991_I319520, ALEPH_1991_S2435284);
60
61}
|
