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 = applyProjection<DISKinematics>(event, "Kinematics");
60
61 const DISRapidityGap& g = applyProjection<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 int kaon=0;
87 int lambda=0;
88
89 for(const Particle& p : fs.particles()){
90 const double eta= p.eta();
91 const double pT = p.pT()/GeV;
92 const int pid = abs(p.pid());
93 //const double ybj= (p.E()-p.pz())/(2*27.5);
94 if (pid == 310 || pid == 130) { //K0S
95 //cout << " pid " << pid << " eta " << eta << endl;
96 if (pT>0.5 && pT<4.0){
97 kaon++ ;
98 //fill histograms related to the kaons in here.
99 _h["pT_kaon"] -> fill(pT,0.5/pT);
100 _h["eta_kaon"] -> fill(eta);
101 _h_multK0_0 -> fill(Q2);
102 _h_multK0_3 -> fill(Q2);
103 if(rgap<1.5 && W>140.0 ) {
104 _h["K0_LRG_data_pT"] -> fill(pT,0.5/pT);
105 _h["K0_LRG_data_eta"] -> fill(eta);
106 //cout<< abs(eta) <<endl;
107 }
108 else if(rgap>1.5 && W>140.0) {
109 _h["K0_NRG_data_pT"] -> fill(pT,0.5/pT);
110 _h["K0_NRG_data_eta"] -> fill(eta);
111 }
112 }
113 }
114 else if (pid==3122){ // Lambda
115 if (pT>0.5 && pT<3.5){
116 lambda++ ;
117 //fill histograms related to the lambdas in here.
118 _h["pT_lambda"] -> fill(pT,0.5/pT);
119 _h["eta_lambda"] -> fill(eta);
120 }
121 }
122 }
123
124 }
125
126
127 /// Normalise histograms etc., after the run
128 void finalize() {
129 divide(_h_multK0_0, _h_multK0_1, _h_scat);
130 divide(_h_multK0_3, _h_multK0_2, _h_scatratio);
131
132
133 //cout<< "#of kaons per events"<< kaon/numEvents() <<endl;
134 //cout<< "Num mean charged p multiplicity"<< *_c["charged"]<< endl;
135 scale(_h["pT_kaon"],1./ *_c["dis"]);
136 scale(_h["eta_kaon"],1./ *_c["dis"]);
137 scale(_h["pT_lambda"],1./ *_c["dis"]);
138 scale(_h["eta_lambda"],1./ *_c["dis"]);
139 scale(_h["K0_LRG_data_pT"],1./ *_c["dis"]);
140 scale(_h["K0_NRG_data_pT"],1./ *_c["dis"]);
141 scale(_h["K0_LRG_data_eta"],1./ *_c["dis"]);
142 scale(_h["K0_NRG_data_eta"],1./ *_c["dis"]);
143
144 }
145
146 ///@}
147
148
149 /// @name Histograms
150 ///@{
151 map<string, Histo1DPtr> _h;
152 map<string, Profile1DPtr> _p;
153 map<string, CounterPtr> _c;
154 ///@}
155 private:
156 Scatter2DPtr _h_scat, _h_scatratio ;
157 Histo1DPtr _h_multK0_0 , _h_multK0_1 ,_h_multK0_2 ,_h_multK0_3 ;
158 };
159
160
161 RIVET_DECLARE_PLUGIN(ZEUS_1995_I395196);
162
163}
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