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121 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief D0 -> K+ K- pi+ pi- and 2pi+2pi-
class CLEO_2017_I1519168 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CLEO_2017_I1519168);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==421);
declare(ufs, "UFS");
DecayedParticles D0(ufs);
D0.addStable(PID::PI0);
D0.addStable(PID::K0S);
D0.addStable(PID::ETA);
D0.addStable(PID::ETAPRIME);
declare(D0, "D0");
// histograms
for(unsigned int ix=0;ix<8;++ix)
book(_h[ix ],1,1,1+ix);
for(unsigned int ix=0;ix<6;++ix)
book(_h[ix+ 8],2,1,1+ix);
for(unsigned int ix=0;ix<4;++ix)
book(_h[ix+14],3,1,1+ix);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// define the decay mode
static const map<PdgId,unsigned int> & mode1 = { { 211,2}, { -211,2}};
static const map<PdgId,unsigned int> & mode2 = { { 321,1}, { -321,1}, { 211,1}, { -211,1}};
DecayedParticles D0 = apply<DecayedParticles>(event, "D0");
// loop over particles
for(unsigned int ix=0;ix<D0.decaying().size();++ix) {
int sign = D0.decaying()[ix].pid()/421;
if ( D0.modeMatches(ix,4,mode1)) {
const Particles & pip= D0.decayProducts()[ix].at( sign*211);
const Particles & pim= D0.decayProducts()[ix].at(-sign*211);
bool KSveto=false;
set<double> mpm;
for(unsigned int ix=0;ix<2;++ix) {
for(unsigned int iy=0;iy<2;++iy) {
double m2 = (pip[ix].momentum()+pim[iy].momentum()).mass2();
double m = sqrt(m2);
mpm.insert(m2);
if(abs(m-0.497611)<0.0165) KSveto=true;
}
}
if(KSveto) continue;
_h[0]->fill(*mpm.begin());
_h[1]->fill(*mpm.rbegin());
for(const double & m2 : mpm) _h[2]->fill(m2);
FourMomentum ppp = pip[0].momentum()+pip[1].momentum();
_h[3]->fill(ppp.mass2());
FourMomentum pmm = pim[0].momentum()+pim[1].momentum();
double m2ppm[2] = {(ppp+pim[0].momentum()).mass2(),(ppp+pim[1].momentum()).mass2()};
if(m2ppm[0]>m2ppm[1]) swap(m2ppm[0],m2ppm[1]);
_h[4]->fill(m2ppm[0]);
_h[5]->fill(m2ppm[1]);
double m2mmp[2] = {(pmm+pip[0].momentum()).mass2(),(pmm+pip[1].momentum()).mass2()};
if(m2mmp[0]>m2mmp[1]) swap(m2mmp[0],m2mmp[1]);
_h[6]->fill(m2mmp[0]);
_h[7]->fill(m2ppm[1]);
}
else if ( D0.modeMatches(ix,4,mode2)) {
const Particles & Kp = D0.decayProducts()[ix].at( sign*321);
const Particles & Km = D0.decayProducts()[ix].at(-sign*321);
const Particles & pip= D0.decayProducts()[ix].at( sign*211);
const Particles & pim= D0.decayProducts()[ix].at(-sign*211);
double mpipi = (pip[0].momentum()+pim[0].momentum()).mass();
if(abs(mpipi-0.497611)<0.0165) continue;
_h[ 8]->fill((Kp [0].momentum()+Km [0].momentum()).mass2());
_h[ 9]->fill((Kp [0].momentum()+pip[0].momentum()).mass2());
_h[10]->fill((Kp [0].momentum()+pim[0].momentum()).mass2());
_h[11]->fill((Km [0].momentum()+pip[0].momentum()).mass2());
_h[12]->fill((Km [0].momentum()+pim[0].momentum()).mass2());
_h[13]->fill(sqr(mpipi));
_h[14]->fill((Kp [0].momentum()+Km [0].momentum()+pip[0].momentum()).mass2());
_h[15]->fill((Kp [0].momentum()+Km [0].momentum()+pim[0].momentum()).mass2());
_h[16]->fill((Kp [0].momentum()+pip[0].momentum()+pim[0].momentum()).mass2());
_h[17]->fill((Km [0].momentum()+pip[0].momentum()+pim[0].momentum()).mass2());
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<18;++ix)
normalize(_h[ix],1.,false);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[18];
/// @}
};
RIVET_DECLARE_PLUGIN(CLEO_2017_I1519168);
}
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