Rivet analyses referenceZEUS_1995_I395196Neutral strange particle production in deep inelastic scattering at HERA (ZEUS)Experiment: ZEUS (HERA) Inspire ID: 395196 Status: VALIDATED Authors:
Beam energies: (26.7, 820.0); (820.0, 26.7) GeV Run details:
Measurements of $K^0$ and $\Lambda$ production in neutral current, deep inelastic scattering of 26.7 GeV electrons and 820 GeV protons in the kinematic range $10<Q^2<640$, $0.0003<x<0.01$, and $y>0.04$. Average multiplicities for $K^0$ and $\Lambda$ production are determined for transverse momenta $p_T >0.5> $ GeV and pseudorapidities $|\eta| < 1.3 $. The production properties of $K^0$ in events with and without a large rapidity gap with respect to the proton direction are compared. The ratio of neutral $K^0$ to charged particles per event in the measured kinematic range is, within the present statistics, the same in both samples. Source code: ZEUS_1995_I395196.cc 1// -*- C++ -*-
2#include "Rivet/Analysis.hh"
3#include "Rivet/Projections/FinalState.hh"
4#include "Rivet/Projections/FastJets.hh"
5#include "Rivet/Projections/DISKinematics.hh"
6#include "Rivet/Projections/DISLepton.hh"
7#include "Rivet/Projections/ChargedFinalState.hh"
8#include "Rivet/Projections/DISRapidityGap.hh"
9namespace Rivet {
10
11
12 /// @brief Neutral strange particle production in deep inelastic scattering at HERA (ZEUS)
13 class ZEUS_1995_I395196 : public Analysis {
14 public:
15
16 /// Constructor
17 RIVET_DEFAULT_ANALYSIS_CTOR(ZEUS_1995_I395196);
18
19
20 void init() {
21
22 declare(DISLepton(), "Lepton");
23 declare(DISKinematics(), "Kinematics");
24 declare(DISRapidityGap(), "Rapidity Gap");
25
26 const Cut cut = Cuts::abseta < 1.3;
27
28 const FinalState fs(cut);
29 declare(fs, "FS");
30
31 const ChargedFinalState cfs(cut);
32 declare(cfs, "CFS");
33
34 // take binning from reference data using HEPData ID (digits in "d01-x01-y01" etc.)
35 book(_h["pT_kaon"], 1, 1, 1);
36 book(_h["eta_kaon"], 2, 1, 1);
37 book(_h["pT_lambda"], 3, 1, 1);
38 book(_h["eta_lambda"], 4, 1, 1);
39 book(_h_multK0_0,"TMP/mult_0", refData(5,1,1));
40 book(_h_multK0_1,"TMP/mult_1", refData(5,1,1));
41 book(_h_multK0_2,"TMP/mult_2", refData(6,1,1));
42 book(_h_multK0_3,"TMP/mult_3", refData(6,1,1));
43 book(_h_scatratio, 6, 1, 1);
44 book(_h["K0_NRG_data_pT"], 7, 1, 1);
45 book(_h["K0_LRG_data_pT"], 8, 1, 1);
46 book(_h["K0_NRG_data_eta"], 9, 1, 1);
47 book(_h["K0_LRG_data_eta"], 10, 1, 1);
48 book(_h_scat,5,1,1);
49 book(_c["dis"],"TMP/Nevt_after_cuts");
50
51
52 }
53
54
55 /// Perform the per-event analysis
56 void analyze(const Event& event) {
57
58 const FinalState& fs = apply<FinalState>(event, "FS");
59 const DISKinematics& dk = apply<DISKinematics>(event, "Kinematics");
60
61 const DISRapidityGap& g = apply<DISRapidityGap>(event, "Rapidity Gap");
62
63 const ChargedFinalState& charged = apply<ChargedFinalState>(event, "CFS");
64 const size_t numPartcharged = charged.particles().size();
65 //const size_t numPart = fs.particles().size();
66 //_c["charged"] -> fill(numPartcharged);
67 //_c["all"] -> fill(numPart);
68 const size_t numParticles = fs.particles().size();
69 if (numParticles < 2) {
70 MSG_DEBUG("Failed leptonic event cut");
71 vetoEvent;
72 }
73
74 double rgap = g.gap();
75 // Get the DIS kinematics
76 double xbj = dk.x();
77 double ybj = dk.y();
78 double Q2 = dk.Q2()/GeV;
79 double W = sqrt(dk.W2()/GeV);
80 bool cut = Q2 >10 && Q2<640 && xbj>0.0003 && xbj<0.01 && ybj>0.04 && ybj<1.0;
81 if (!cut) vetoEvent;
82 _h_multK0_1 -> fill(Q2);
83 _h_multK0_2 -> fill(Q2,numPartcharged);
84
85 _c["dis"] -> fill();
86
87 for(const Particle& p : fs.particles()){
88 const double eta= p.eta();
89 const double pT = p.pT()/GeV;
90 const int pid = abs(p.pid());
91 //const double ybj= (p.E()-p.pz())/(2*27.5);
92 if (pid == 310 || pid == 130) { //K0S
93 //cout << " pid " << pid << " eta " << eta << endl;
94 if (pT>0.5 && pT<4.0){
95 //fill histograms related to the kaons in here.
96 _h["pT_kaon"] -> fill(pT,0.5/pT);
97 _h["eta_kaon"] -> fill(eta);
98 _h_multK0_0 -> fill(Q2);
99 _h_multK0_3 -> fill(Q2);
100 if(rgap<1.5 && W>140.0 ) {
101 _h["K0_LRG_data_pT"] -> fill(pT,0.5/pT);
102 _h["K0_LRG_data_eta"] -> fill(eta);
103 //cout<< abs(eta) <<endl;
104 }
105 else if(rgap>1.5 && W>140.0) {
106 _h["K0_NRG_data_pT"] -> fill(pT,0.5/pT);
107 _h["K0_NRG_data_eta"] -> fill(eta);
108 }
109 }
110 }
111 else if (pid==3122){ // Lambda
112 if (pT>0.5 && pT<3.5){
113 //fill histograms related to the lambdas in here.
114 _h["pT_lambda"] -> fill(pT,0.5/pT);
115 _h["eta_lambda"] -> fill(eta);
116 }
117 }
118 }
119
120 }
121
122
123 /// Normalise histograms etc., after the run
124 void finalize() {
125 divide(_h_multK0_0, _h_multK0_1, _h_scat);
126 divide(_h_multK0_3, _h_multK0_2, _h_scatratio);
127
128
129 //cout<< "#of kaons per events"<< kaon/numEvents() <<endl;
130 //cout<< "Num mean charged p multiplicity"<< *_c["charged"]<< endl;
131 scale(_h["pT_kaon"],1./ *_c["dis"]);
132 scale(_h["eta_kaon"],1./ *_c["dis"]);
133 scale(_h["pT_lambda"],1./ *_c["dis"]);
134 scale(_h["eta_lambda"],1./ *_c["dis"]);
135 scale(_h["K0_LRG_data_pT"],1./ *_c["dis"]);
136 scale(_h["K0_NRG_data_pT"],1./ *_c["dis"]);
137 scale(_h["K0_LRG_data_eta"],1./ *_c["dis"]);
138 scale(_h["K0_NRG_data_eta"],1./ *_c["dis"]);
139
140 }
141
142 ///@}
143
144
145 /// @name Histograms
146 ///@{
147 map<string, Histo1DPtr> _h;
148 map<string, Profile1DPtr> _p;
149 map<string, CounterPtr> _c;
150 ///@}
151 private:
152 Estimate1DPtr _h_scat, _h_scatratio ;
153 Histo1DPtr _h_multK0_0 , _h_multK0_1 ,_h_multK0_2 ,_h_multK0_3 ;
154 };
155
156
157 RIVET_DECLARE_PLUGIN(ZEUS_1995_I395196);
158
159}
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