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Rivet analyses reference

STAR_2016_I1414638

Beam energy dependence of the third harmonic of azimuthal correlations
Experiment: STAR (RHIC)
Inspire ID: 1414638
Status: UNVALIDATED
Authors:
  • Maria Stefaniak
  • Christian Bierlich
References:
  • Phys.Rev.Lett. 116 (2016) no.11, 112302
  • DOI: 10.1103/PhysRevLett.116.112302
  • arXiv: 1601.01999
Beams: 1000791970 1000791970
Beam energies: (758.5, 758.5); (1132.8, 1132.8); (1428.2, 1428.2); (1930.6, 1930.6); (2659.5, 2659.5); (3841.5, 3841.5); (6146.4, 6146.4); (19700.0, 19700.0) GeV
Run details:
  • Minimum bias AuAu events at various collision energies. Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples.

Results of harmonic decomposition of two-particle azimuthal correlations in AuAu collisions, in energies recorded in the beam energy scan. For MC purposes, note that the lowest energies might be too low for standard generators to even initialise. Beam energy must be specified as analysis option "ENERGY" when rivet-merging samples.

Source code: STAR_2016_I1414638.cc
 1// -*- C++ -*-
 2#include "Rivet/Analysis.hh"
 3#include "Rivet/Projections/FinalState.hh"
 4#include "Rivet/Projections/ChargedFinalState.hh"
 5#include "Rivet/Projections/SingleValueProjection.hh"
 6#include "Rivet/Projections/ImpactParameterProjection.hh"
 7#include "Rivet/Tools/Percentile.hh"
 8#include "Rivet/Tools/RHICCommon.hh"
 9#include <complex>
10
11namespace Rivet {
12
13  /// @brief Third harmonic of azimuthal correlations in Au+Au collisions 
14  //  at different COM energies.
15  class STAR_2016_I1414638 : public Analysis {
16  public: 
17    /// Constructor	  
18    STAR_2016_I1414638 () : Analysis("STAR_2016_I1414638") {}
19
20    void init() {
21	/// Projections
22	/// The centrality projection. 
23	declareCentrality(STAR_BES_Centrality(), 
24	  "STAR_BES_CALIB", "CMULT", "CMULT");
25
26	/// The observed particles.
27    	declare(ChargedFinalState(Cuts::abseta < 1.0 &&
28			       	   Cuts::pT > 0.2*GeV), "CFS");
29	/// The centrality bins
30	centralityBins = {5., 10, 20, 30, 40, 50, 60, 70, 80};
31	/// The corresponding histograms for the different analysis energies.
32	vector<double> energies = {7.7, 11.5, 14.5, 19.6, 27.0, 39.0, 
33	  62.4, 200.0};
34	int energy = -1;
35	for (int i = 0, N = energies.size(); i < N; ++i) {
36	  if (isCompatibleWithSqrtS(197.*energies[i],1E-1)) energy = i;
37	}
38	if (energy == -1) MSG_ERROR("Incompatible beam energy!");
39	for (int i = 0; i < 9; ++i)
40	  book(h_v32[centralityBins[i]], 1 + i + 9 * energy, 1, 1);
41    }
42
43
44    /// Perform the per-event analysis
45    void analyze(const Event& event) {
46      const ChargedFinalState& cfs = applyProjection<ChargedFinalState>(event, "CFS");
47      // Require at least two charged particles for the analysis to make sense.
48      // No further triggers are described in the paper.
49      const Particles& particles = cfs.particles();
50      if (particles.size() < 2) return;
51      // The centrality projection
52      const CentralityProjection& cent = apply<CentralityProjection>(event,"CMULT");
53      const double c = cent();
54      // Find the correct histogram to fill.
55      auto hItr = h_v32.upper_bound(c);
56      if (hItr == h_v32.end()) return;
57      for(int i = 0, N = particles.size(); i < N; ++i){
58        for(int j = i + 1; j < N; ++j){
59          const double eta1 = particles[i].eta();
60	  const double eta2 = particles[j].eta();
61	  if(eta1 * eta2 < 0){
62            const double deltaPhi = abs(particles[i].phi() - particles[j].phi());
63            // Fill profile with v_2(2)^2 from eq. (1) in the paper.
64	    hItr->second->fill(abs(eta1 - eta2), cos(3.*deltaPhi));
65          }
66        }
67       }
68    }
69    
70    /// Normalise histograms etc., after the run
71    void finalize() {
72    
73    }
74
75    //@}
76
77
78    /// @name Histograms
79    //@{
80    // The centralities.
81    vector<double> centralityBins;
82    // The histograms.
83    map<double, Profile1DPtr> h_v32;
84    //@}
85
86
87  };
88
89
90  // The hook for the plugin system
91  RIVET_DECLARE_PLUGIN(STAR_2016_I1414638);
92
93}