Rivet Analyses Reference
NA22_1986_I18431
Multiplicity distributions in $pp$, $K^+ p$ and $\pi^+ p$ at $p_{\mathrm{lab}} = 250$ GeV/c
Experiment: NA22 (SPS)
Inspire ID: 18431
Status: VALIDATED
Authors:References:Beams: p+ p+, 321 p+, 211 p+
Beam energies: (250.0, 0.0); (250.0, 0.0); (250.0, 0.0) GeV
Run details:- Fixed target events with $p$, $K^+$ and $\pi^+$ hitting a proton target.
Charged multiplicity distributions of $pp$, $K^+ p$ and $\pi^+ p$ fixed target collisions, $p_{\mathrm{lab}} = 250$ GeV/c or equivalently $\sqrt{s} = 21.7$ GeV/c (pp).
Source code:
NA22_1986_I18431.cc 1
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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
namespace Rivet {
/// NA22 min bias multiplicity distributions.
class NA22_1986_I18431 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(NA22_1986_I18431);
/// @name Analysis methods
///@{
/// Book histograms and initialise projections before the run
void init() {
declare(ChargedFinalState(), "CFS");
// Figure out beam type
const ParticlePair& beam = beams();
int btype = 0;
if (beam.first.pid() == PID::PIPLUS && beam.second.pid() == PID::PROTON)
btype = 1;
else if (beam.first.pid() == PID::KPLUS && beam.second.pid() == PID::PROTON)
btype = 2;
else if (beam.first.pid() == PID::PROTON && beam.second.pid() == PID::PROTON)
btype = 3;
else {
MSG_ERROR("Beam error: Not compatible!");
return;
}
// Book histo for appropriate beam type
book(_h_mult, btype, 1, 1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
size_t nfs = apply<ChargedFinalState>(event, "CFS").size();
if (nfs >= 30) nfs = 30;
_h_mult->fill(nfs);
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_h_mult, 2.0); // normalize to 2 to account for bin width
}
///@}
/// @name Histograms
//@{
Histo1DPtr _h_mult;
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(NA22_1986_I18431);
}
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