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103 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief D+ -> omega e+ nu_e
class BESIII_2015_I1386254 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BESIII_2015_I1386254);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::pid==411);
declare(ufs, "UFS");
DecayedParticles DD(ufs);
DD.addStable(PID::PI0);
DD.addStable(PID::K0S);
DD.addStable(PID::ETA);
DD.addStable(PID::ETAPRIME);
declare(DD, "DD");
// Book histograms
for(unsigned int ix=0;ix<4;++ix)
book(_h[ix],1,1,1+ix);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode = { { 211,1}, {-211,1}, { 111,1}, {-11,1}, { 12,1}};
DecayedParticles DD = apply<DecayedParticles>(event, "DD");
// loop over particles
for(unsigned int ix=0;ix<DD.decaying().size();++ix) {
if(!DD.modeMatches(ix,5,mode)) continue;
const Particle & pip= DD.decayProducts()[ix].at( 211)[0];
const Particle & pim= DD.decayProducts()[ix].at(-211)[0];
const Particle & pi0= DD.decayProducts()[ix].at( 111)[0];
const Particle & ep = DD.decayProducts()[ix].at(-11)[0];
const Particle & nue= DD.decayProducts()[ix].at( 12)[0];
FourMomentum pOmega = pip.momentum()+pim.momentum()+pi0.momentum();
_h[0]->fill(pOmega.mass2());
FourMomentum qq = DD.decaying()[ix].momentum()-pOmega;
_h[1]->fill(qq.mass2());
// boost momenta to D rest frame
LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(DD.decaying()[ix].momentum().betaVec());
FourMomentum pPP = boost.transform(pOmega);
Matrix3 ptoz(-pPP.p3().unit(), Vector3(0,0,1));
boost.preMult(ptoz);
// the momenta in frane to W along z
FourMomentum pD = boost.transform(DD.decaying()[ix].momentum());
FourMomentum ppip = boost.transform(pip.momentum());
FourMomentum ppim = boost.transform(pim.momentum());
FourMomentum ppi0 = boost.transform(pi0.momentum());
FourMomentum pe = boost.transform(ep .momentum());
FourMomentum pnu = boost.transform(nue.momentum());
pOmega = ppip+ppim+ppi0;
qq = pD-pOmega;
LorentzTransform boostOmega = LorentzTransform::mkFrameTransformFromBeta(pOmega.betaVec());
Vector3 n1 = (boostOmega.transform(ppip).p3().cross(boostOmega.transform(ppim).p3())).unit();
_h[2]->fill(n1.dot(pOmega.p3().unit()));
LorentzTransform boostW = LorentzTransform::mkFrameTransformFromBeta( qq.betaVec());
Vector3 axisE = boostW.transform(pe).p3().unit();
_h[3]->fill(axisE.dot(qq.p3().unit()));
// axisOmega.setZ(0.);
// axisE.setZ(0.);
// double chi = atan2(axisE.cross(axisOmega).dot(qq.p3().unit()), axisE.dot(axisOmega));
// _h[imode+4]->fill(chi);
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<4;++ix)
normalize(_h[ix]);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[4];
/// @}
};
RIVET_DECLARE_PLUGIN(BESIII_2015_I1386254);
}
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