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Rivet analyses reference
ZEUS_1996_I420332
Measurement of the F2 structure function in deep inelastic e+ p scattering using 1994 data from the ZEUS detector at HERA
Experiment: ZEUS (HERA)
Inspire ID: 420332
Status: VALIDATED
Authors:
References:
- Z.Phys.C 72 (1996) 399, DOI:10.1007/s002880050260,10.1007/BF02909169, - hep-ex/9607002
Beams: e+ p+, p+ e+
Beam energies: (27.5, 820.0); (820.0, 27.5) GeV
We present measurements of the structure function $F_2$ in ep scattering at HERA in the range $ 3.5 < Q^2 < 5000 $ GeV$^2$. A new reconstruction method has allowed a significant improvement in the resolution of the kinematic variables and an extension of the kinematic region covered by the experiment. At $Q^2 < 35 $ GeV$^2$ the range in $x$ now spans $ 6.3 \cdot 10^{-5} < x < 0.08$ providing overlap with measurements from fixed target experiments. At values of $Q^2$ above 1000 GeV$^2$ the $x$ range extends to 0.5.
Source code:
ZEUS_1996_I420332.cc
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122 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/DISKinematics.hh"
namespace Rivet {
/// @brief F2 structure function in DIS e+ p (ZEUS)
class ZEUS_1996_I420332 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ZEUS_1996_I420332);
/// @name Analysis methods
///@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
// Initialise and register projections
declare(DISLepton(), "Lepton");
declare(DISKinematics(), "Kinematics");
Histo1DPtr dummy;
_h_f2.add( 3.2, 4.0,book(dummy,1,1,1));
_h_f2.add( 4.0, 5.0,book(dummy,2,1,1));
_h_f2.add( 5.0, 7.0,book(dummy,3,1,1));
_h_f2.add( 7.0, 9.0,book(dummy,5,1,1));
_h_f2.add( 9.0, 11.0,book(dummy,6,1,1));
_h_f2.add( 11.0, 13.0,book(dummy,8,1,1));
_h_f2.add( 13.0, 16.0,book(dummy,9,1,1));
_h_f2.add( 16.0, 20.0,book(dummy,11,1,1));
_h_f2.add( 20., 32, book(dummy,13,1,1));
_h_f2.add( 32., 40., book(dummy,15,1,1));
_h_f2.add( 40., 50., book(dummy,17,1,1));
_h_f2.add( 50., 65., book(dummy,18,1,1));
_h_f2.add( 65., 85., book(dummy,19,1,1));
_h_f2.add( 85., 110.,book(dummy,20,1,1));
_h_f2.add( 110., 140.,book(dummy,21,1,1));
_h_f2.add( 140., 185.,book(dummy,22,1,1));
_h_f2.add( 185., 240.,book(dummy,23,1,1));
_h_f2.add( 240., 310.,book(dummy,24,1,1));
_h_f2.add( 310., 410.,book(dummy,25,1,1));
_h_f2.add( 410., 530.,book(dummy,26,1,1));
_h_f2.add( 530., 710.,book(dummy,27,1,1));
_h_f2.add( 710., 900.,book(dummy,28,1,1));
_h_f2.add( 900., 1300.,book(dummy,29,1,1));
_h_f2.add( 1300., 1800.,book(dummy,30,1,1));
_h_f2.add( 1800., 2500.,book(dummy,31,1,1));
_h_f2.add( 2500., 3500.,book(dummy,32,1,1));
_h_f2.add( 3500., 15000.,book(dummy,33,1,1));
/*
book(_hist_Q2_10, "Q2_10",100,1., 11.0);
book(_hist_Q2_100, "Q2_100",100,10., 100.0);
book(_hist_Q2_1000, "Q2_1000",100,100., 1000.0);
book(_hist_Q2_2000, "Q2_2000",100,800., 5000.0);
book(_hist_Q2_3000, "Q2_3000",100,3000., 10000.0);
*/
}
/// Perform the per-event analysis
void analyze(const Event& event) {
const DISKinematics& dk = applyProjection<DISKinematics>(event, "Kinematics");
//const DISLepton& dl = applyProjection<DISLepton>(event,"Lepton");
// Get the DIS kinematics
double x = dk.x();
double y = dk.y();
double Q2 = dk.Q2()/GeV;
// Flux factor
const double alpha = 7.29927e-3;
double F = x*pow(Q2,2.)/(2.0*M_PI*pow(alpha,2.)*(1.0+pow((1.-y),2.)));
/*
_hist_Q2_10-> fill(Q2) ;
_hist_Q2_100-> fill(Q2) ;
_hist_Q2_1000-> fill(Q2) ;
_hist_Q2_2000-> fill(Q2) ;
_hist_Q2_3000-> fill(Q2) ;
*/
_h_f2.fill(Q2,x,F); // wypelniamy histogram x w skali Q2
}
/// Normalise histograms etc., after the run
void finalize() {
double gev2nb =0.389e6;
double scalefactor=crossSection()/nanobarn/sumOfWeights()/gev2nb ;
// with _h_f2.scale also q2 bin width is scaled
_h_f2.scale(scalefactor, this);
}
///@}
/// @name Histograms
///@{
BinnedHistogram _h_f2;
Histo1DPtr _hist_Q2_10,_hist_Q2_100,_hist_Q2_1000,_hist_Q2_2000,_hist_Q2_3000;
///@}
};
RIVET_DECLARE_PLUGIN(ZEUS_1996_I420332);
}
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