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Rivet analyses reference
BESIII_2023_I2621481
$D^{0,+}\to\pi^+\pi^+\pi^-+X$ decays
Experiment: BESIII (BEPC)
Inspire ID: 2621481
Status: VALIDATED NOHEPDATA
Authors:
References:
Beams: e+ e-
Beam energies: (2.4, 2.4) GeV
Run details:
- Needs e+e- events at 4.773 due cuts
Measurement of mass and momentum distributions in $D^{0,+}\to\pi^+\pi^+\pi^-+X$ decays. The mass distribution was read from table VII in the paper and is corrected while the momentum distributions were extracted from the figures and are background subtracted but not corrected.
Source code:
BESIII_2023_I2621481.cc
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95 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief D0,+ -> pi+ pi+ pi- +X
class BESIII_2023_I2621481 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2023_I2621481);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// projections
declare(UnstableParticles(Cuts::abspid==411 or
Cuts::abspid==421),"UFS");
// histos
for(unsigned int ix=0;ix<2;++ix) {
book(_h_br [ix],1,1,1+ix);
book(_h_mass[ix],2,1,1+ix);
for(unsigned int iy=0;iy<3;++iy)
book(_h_mom[ix][iy],3,1+ix,1+iy);
book(_c[ix],"TMP/nD_"+toString(ix+1));
}
}
void findChildren(const Particle & p, Particles & piPlus, Particles & piMinus) {
for( const Particle &child : p.children()) {
if(child.pid()==PID::PIPLUS) {
piPlus.push_back(child);
}
else if(child.pid()==PID::PIMINUS) {
piMinus.push_back(child);
}
else if(child.pid()==PID::K0S || child.pid()==PID::K0L)
continue;
else if(!child.children().empty())
findChildren(child,piPlus,piMinus);
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
for (const Particle& p : apply<FinalState>(event, "UFS").particles()) {
unsigned int iloc = p.abspid()==421 ? 0 : 1;
_c[iloc]->fill();
Particles piPlus,piMinus;
findChildren(p,piPlus,piMinus);
if(p.pid()<0) swap(piPlus,piMinus);
if(piPlus.size()>=2 && !piMinus.empty()) {
_h_br[iloc]->fill(.5);
sortBy(piMinus,cmpMomByP);
sortBy(piPlus ,cmpMomByP);
_h_mom[iloc][2]->fill(piMinus[0].p3().mod());
for(unsigned int ix=0;ix<2;++ix)
_h_mom[iloc][ix]->fill(piPlus[ix].p3().mod());
double mass = (piMinus[0].momentum()+piPlus[0].momentum()+piPlus[1].momentum()).mass();
_h_mass[iloc]->fill(mass);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<2;++ix) {
scale(_h_br [ix], 100./ *_c[ix]);
scale(_h_mass[ix], 100./ *_c[ix]);
for(unsigned int iy=0;iy<3;++iy)
normalize(_h_mom[ix][iy],1.,false);
}
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h_br[2],_h_mass[2],_h_mom[2][3];
CounterPtr _c[2];
/// @}
};
RIVET_DECLARE_PLUGIN(BESIII_2023_I2621481);
}
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