// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief D_s+ -> pi+pi+pi-
class E791_2001_I530319 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(E791_2001_I530319);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==431);
declare(ufs, "UFS");
DecayedParticles DS(ufs);
DS.addStable(PID::PI0);
DS.addStable(PID::K0S);
declare(DS,"DS");
// histos
book(_h_pi,1,1,1);
book(_dalitz, "dalitz",50,0.,3.5,50,0.0,3.5);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode = { { 211,2}, {-211,1}};
static const map<PdgId,unsigned int> & modeCC = { {-211,2}, { 211,1}};
DecayedParticles DS = apply<DecayedParticles>(event, "DS");
// loop over particles
for(unsigned int ix=0;ix<DS.decaying().size();++ix) {
int sign = 1;
if (DS.decaying()[ix].pid()>0 && DS.modeMatches(ix,3,mode)) {
sign=1;
}
else if (DS.decaying()[ix].pid()<0 && DS.modeMatches(ix,3,modeCC)) {
sign=-1;
}
else
continue;
const Particles & pip = DS.decayProducts()[ix].at( sign*211);
const Particle & pim = DS.decayProducts()[ix].at(-sign*211)[0];
double m1 = (pim.momentum()+pip[0].momentum()).mass2();
double m2 = (pim.momentum()+pip[1].momentum()).mass2();
_h_pi->fill(m1);
_h_pi->fill(m2);
_dalitz->fill(m1,m2);
_dalitz->fill(m2,m1);
}
}
/// Normalise histograms etc., after the run
void finalize() {
normalize(_h_pi);
normalize(_dalitz);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h_pi;
Histo2DPtr _dalitz;
/// @}
};
RIVET_DECLARE_PLUGIN(E791_2001_I530319);
}