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Rivet analyses reference
BESIII_2020_I1818254
$\chi_{c(0,1,2)}\to \Sigma^0 \bar{p} K^+$ + c.c
Experiment: BESIII (BEPC)
Inspire ID: 1818254
Status: VALIDATED NOHEPDATA
Authors:
References:
- Phys.Rev.D 102 (2020) 9, 092006
Beams: * *
Beam energies: ANY
Run details:
- Any process producing chi_c originally e+e-
Measurement of the mass distributions in the decays $\chi_{c(0,1,2)}\to \Sigma^0 \bar{p} K^+$ + c.c. The data were read from the plots in the paper and may not be corrected for efficiency or background.
Source code:
BESIII_2020_I1818254.cc
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98 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief chi_c -> pbar Sigma0 K+
class BESIII_2020_I1818254 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2020_I1818254);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
UnstableParticles ufs = UnstableParticles(Cuts::pid==20443 or
Cuts::pid==445 or
Cuts::pid==10441);
declare(ufs, "UFS");
DecayedParticles chi(ufs);
chi.addStable( PID::PI0);
chi.addStable( PID::K0S);
chi.addStable( PID::ETA);
chi.addStable( PID::ETAPRIME);
chi.addStable( PID::SIGMA0);
chi.addStable(-PID::SIGMA0);
declare(chi, "chi");
for(unsigned int ix=0;ix<3;++ix) {
book(_dalitz[ix], "dalitz_"+toString(ix+1),50,2.5,7.,50,1.8,6.);
for(unsigned int iy=0;iy<3;++iy) {
book(_h[ix][iy],1+ix,1,1+iy);
}
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode = { {-2212,1}, { 3212,1}, { 321,1} };
static const map<PdgId,unsigned int> & modeCC = { { 2212,1}, {-3212,1}, {-321,1} };
DecayedParticles chi = apply<DecayedParticles>(event, "chi");
// loop over particles
for(unsigned int ix=0;ix<chi.decaying().size();++ix) {
int sign=1;
if(chi.modeMatches(ix,3,mode)) {
sign = 1;
}
else if(chi.modeMatches(ix,3,modeCC)) {
sign = -1;
}
else continue;
unsigned int iloc = chi.decaying()[ix].pid()==10441 ? 0 : chi.decaying()[ix].pid()==445 ? 2 : 1;
const Particle & Kp = chi.decayProducts()[ix].at( sign*321)[0];
const Particle & pbar = chi.decayProducts()[ix].at(-sign*2212)[0];
const Particle & sig = chi.decayProducts()[ix].at(sign*3212)[0];
double mpK = (Kp .momentum()+pbar.momentum()).mass2();
double msigK = (Kp .momentum()+sig .momentum()).mass2();
double msigp = (sig.momentum()+pbar.momentum()).mass2();
_h[iloc][0]->fill(sqrt(mpK));
_h[iloc][1]->fill(sqrt(msigK));
_h[iloc][2]->fill(sqrt(msigp));
_dalitz[iloc]->fill(msigK,mpK);
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<3;++ix) {
normalize(_dalitz[ix]);
for(unsigned int iy=0;iy<3;++iy) {
normalize(_h[ix][iy]);
}
}
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[3][3];
Histo2DPtr _dalitz[3];
/// @}
};
RIVET_DECLARE_PLUGIN(BESIII_2020_I1818254);
}
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