Rivet analyses referenceHERA_2015_I1377206Measurement of sigma_red (F2) of H1 and ZEUS at different beam energiesExperiment: H1 (HERA) Inspire ID: 1377206 Status: VALIDATED Authors:
Beam energies: (27.5, 920.0); (920.0, 27.5); (27.5, 820.0); (820.0, 27.5); (27.5, 575.0); (575.0, 27.5); (27.5, 460.0); (460.0, 27.5) GeV Run details:
A combination is presented of all inclusive deep inelastic cross sections previously published by the H1 and ZEUS collaborations at HERA for neutral and charged current ep scattering for zero beam polarisation. The data were taken at proton beam energies of 920, 820, 575 and 460 GeV and an electron beam energy of 27.5GeV. The data correspond to an integrated luminosity of about 1 fb^-1 and span six orders of magnitude in negative four-momentum-transfer squared, Q2, and Bjorken x . The correlations of the systematic uncertainties were evaluated and taken into account for the combination. The combined cross sections were input to QCD analyses at leading order, next-to-leading order and at next-to-next-to-leading order, providing a new set of parton distribution functions, called HERAPDF2.0.. The energy and beam options need to be specified when using rivet-merge. Source code: HERA_2015_I1377206.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/Beam.hh"
7
8namespace Rivet {
9
10
11 /// @brief Measurement of sigma_red (F2) of H1 and ZEUS at different beam energies
12 class HERA_2015_I1377206 : public Analysis {
13 public:
14
15 /// Constructor
16 RIVET_DEFAULT_ANALYSIS_CTOR(HERA_2015_I1377206);
17
18
19 /// @name Analysis methods
20 /// @{
21
22 /// Book histograms and initialise projections before the run
23 void init() {
24
25 // Initialise and register projections
26 declare(FinalState(Cuts::abseta < 5 && Cuts::pT > 100*MeV), "FS");
27 declare(DISLepton(), "Lepton");
28 declare(DISKinematics(), "Kinematics");
29
30 string beamOpt = getOption<string>("BEAM","NONE");
31 if (beamOpt == "NONE") {
32 const ParticlePair& beam = beams();
33 _positron = (beam.first.pid() == PID::POSITRON || beam.second.pid() == PID::POSITRON);
34 }
35 else {
36 if (beamOpt == "EMINUS") _positron = false;
37 else if (beamOpt == "EPLUS") _positron = true;
38 else {
39 throw BeamError("Beam species not supported\n");
40 }
41 }
42
43 // Book beams-dependent histograms
44 const double eps = 1e-2;
45 for (double eVal : allowedEnergies()) {
46 const string en = toString(int(eVal)) + toString(_positron);
47 if (isCompatibleWithSqrtS(eVal, eps)) _sqs = en;
48
49 if (fuzzyEquals(eVal, 318.1, eps) && _positron) {
50 // NC e+ p at sqrts=318
51 const vector<double> Q2edges = {
52 0.1, 0.15, 0.2, 0.3, 0.4, 0.45, 0.6, 0.7, 1.0, 1.1, 1.3, 1.7, 2.3,
53 3.1, 3.8, 5.3, 8.0, 9.1, 11., 13., 17.4, 19.1, 25.8, 28., 30., 42.,
54 49., 54., 65., 75., 108., 134., 180., 225., 280., 325., 355., 455., 460.,
55 545., 560., 765., 770., 835., 900., 1120., 1295., 1300., 1755., 1800.,
56 2270., 2500., 3685., 4000., 6520., 7000., 9275., 10000., 15000., 17000.,
57 24770., 25000., 42000.
58 };
59 book(_g[en+"sigred"], Q2edges);
60 _g[en+"sigred"]->maskBins({9, 24, 27, 36, 38, 40, 42, 44, 47, 49, 51, 53, 55, 57, 59, 61});
61 size_t idx = 0;
62 for (auto& b : _g[en+"sigred"]->bins()) {
63 book(b, 1, 1, ++idx);
64 }
65 // CC e+ p at sqrts=318
66 book(_g[en+"sigred_cc"], {280., 325., 460., 545., 900., 1120., 1300., 1755., 1800., 2270.,
67 2500., 3685., 4000., 6520., 7000., 9275., 10000., 20000., 42000.});
68 _g[en+"sigred_cc"]->maskBins({2, 4, 6, 8, 10, 12, 14, 16});
69 idx = 0;
70 for (auto& b : _g[en+"sigred_cc"]->bins()) {
71 book(b, 6, 1, ++idx);
72 }
73 }
74 else if (fuzzyEquals(eVal, 300.3, eps) && _positron) {
75 // NC e+ p at sqrts=300
76 const vector<double> Q2edges = {
77 0.01, 0.05, 0.07, 0.09, 0.12, 0.18, 0.22, 0.32, 0.4, 0.45, 0.6, 0.7, 1.0, 1.1, 1.3,
78 1.7, 2.3, 3.1, 3.8, 5.3, 8., 9.1, 11., 13., 17.4, 19.1, 25.8, 28., 30., 42., 49.,
79 54., 65., 75., 108., 134., 180., 225., 280., 325., 355., 455., 460., 545., 560.,
80 765., 770., 835., 900., 1120., 1295., 1300., 1755., 1800., 2270., 2500., 3685.,
81 4000., 6520., 7000., 9275., 10000., 15000., 17000., 24770., 25000., 42000.
82 };
83 book(_g[en+"sigred"], Q2edges);
84 _g[en+"sigred"]->maskBins({13, 28, 31, 40, 42, 44, 46, 48, 51, 53, 55, 57, 59, 61, 63, 65});
85 size_t idx = 0;
86 for (auto& b : _g[en+"sigred"]->bins()) {
87 book(b, 2, 1, ++idx);
88 }
89 }
90 else if (fuzzyEquals(eVal, 251.5, eps) && _positron) {
91 // NC e+ p at sqrts=251
92 const vector<double> Q2edges = {
93 1., 1.7, 2.3, 3.1, 3.8, 5.3, 8., 9.1, 11., 13., 17.4, 22.1, 28.,
94 30., 42., 49., 54., 65., 75., 108., 134., 180., 225., 280., 325.,
95 355., 455., 460., 545., 560., 765., 770., 835.
96 };
97 book(_g[en+"sigred"], Q2edges);
98 _g[en+"sigred"]->maskBins({8, 13, 16, 18, 25, 27, 29, 31});
99 size_t idx = 0;
100 for (auto& b : _g[en+"sigred"]->bins()) {
101 book(b, 3, 1, ++idx);
102 }
103 }
104 else if (fuzzyEquals(eVal, 224.9, eps) && _positron) {
105 // NC e+ p at sqrts=225
106 const vector<double> Q2edges = {
107 1., 1.7, 2.3, 3.1, 3.8, 5.3, 8., 9.1, 11., 13., 17.4, 22.1, 28.,
108 30., 42., 49., 54., 65., 75., 108., 134., 180., 225., 280., 325.,
109 355., 455., 460., 545., 560., 765., 770., 835.
110 };
111 book(_g[en+"sigred"], Q2edges);
112 _g[en+"sigred"]->maskBins({8, 13, 16, 18, 25, 27, 29, 31});
113 size_t idx = 0;
114 for (auto& b : _g[en+"sigred"]->bins()) {
115 book(b, 4, 1, ++idx);
116 }
117 }
118 else if (fuzzyEquals(eVal, 318.1, eps) && !_positron) {
119 // NC e- p at sqrts=318
120 const vector<double> Q2edges = {
121 54., 65., 75., 108., 134., 180., 225., 280., 325., 355., 455.,
122 460., 545., 560., 765., 770., 835., 900., 1120., 1295., 1300.,
123 1755., 1800., 2270., 2500., 3685., 4000., 6520., 7000., 9275.,
124 10000., 15000., 17000., 24770., 25000., 42000., 70000.
125 };
126 book(_g[en+"sigred"], Q2edges);
127 _g[en+"sigred"]->maskBins({2, 9, 11, 13, 15, 17, 20, 22, 24, 26, 28, 30, 32, 34});
128 size_t idx = 0;
129 for (auto& b : _g[en+"sigred"]->bins()) {
130 book(b, 5, 1, ++idx);
131 }
132 // CC e- p at sqrts=318
133 book(_g[en+"sigred_cc"], {280., 325., 460., 545., 900., 1120., 1300., 1755., 1800., 2270.,
134 2500., 3685., 4000., 6520., 7000., 9275., 10000., 20000., 42000.});
135 _g[en+"sigred_cc"]->maskBins({2, 4, 6, 8, 10, 12, 14, 16});
136 idx = 0;
137 for (auto& b : _g[en+"sigred_cc"]->bins()) {
138 book(b, 7, 1, ++idx);
139 }
140 } // end of if
141 } // end of for
142 if (_sqs == "" && !merging()) {
143 throw BeamError("Invalid beam energy for " + name() + "\n");
144 }
145 } // end of init
146
147
148 void analyze(const Event& event) {
149
150 /// @todo Do the event by event analysis here
151 const DISKinematics& dk = apply<DISKinematics>(event, "Kinematics");
152 const DISLepton& dl = apply<DISLepton>(event,"Lepton");
153
154 // Get the DIS kinematics
155 double x = dk.x();
156 double y = dk.y();
157 double Q2 = dk.Q2()/GeV;
158
159 // Flux factor
160 const double alpha = 7.29927e-3;
161 // GF = 1.16638e-5 Fermi constant
162 const double GF2 = 1.16638e-5*1.16638e-5;
163 // MW = 80.385 W-boson mass
164 const double MW2 = 80.385 * 80.385;
165
166 if (PID::isNeutrino(dl.out().abspid()) ) {
167 // fill histo for CC
168 double F = 2.0*M_PI*x/GF2 * sqr((MW2 + Q2)/MW2);
169 _g[_sqs+"sigred_cc"]->fill(Q2,x,F); // fill histogram x,Q2
170 }
171 else {
172 // fill histo for NC
173 double F = x*sqr(Q2)/(2.0*M_PI*sqr(alpha)*(1.0+sqr(1-y)));
174 _g[_sqs+"sigred"]->fill(Q2,x,F); // fill histogram x,Q2
175 }
176 }
177
178
179 /// Normalise histograms etc., after the run
180 void finalize() {
181 const double gev2nb = 0.389e6;
182 const double scalefactor=crossSection()/nanobarn/sumOfWeights()/gev2nb ;
183 // with _h_sigred.scale also q2 bin width is scaled
184 scale(_g, scalefactor);
185 divByGroupWidth(_g);
186 }
187
188 /// @}
189
190
191 /// @name Histograms
192 /// @{
193 map<string,Histo1DGroupPtr> _g;
194
195 string _sqs = "";
196
197 bool _positron;
198 /// @}
199
200 };
201
202
203 RIVET_DECLARE_PLUGIN(HERA_2015_I1377206);
204
205}
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