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115 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief B -> p Lambda D
class BELLE_2015_I1392799 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2015_I1392799);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==511);
declare(ufs, "UFS");
DecayedParticles B0(ufs);
B0.addStable( 411);
B0.addStable(-411);
B0.addStable( 413);
B0.addStable(-413);
B0.addStable(PID::LAMBDA);
B0.addStable(-PID::LAMBDA);
declare(B0, "B0");
//histograms
for(unsigned int ix=0;ix<2;++ix) {
for(unsigned int iy=0;iy<2;++iy) {
book(_h[ix][iy],1+ix,1,1+iy);
}
}
book(_nB,"/TMP/nb");
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode1 = { { 2212,1},{-3122,1}, {-411,1}};
static const map<PdgId,unsigned int> & mode1CC = { {-2212,1},{ 3122,1}, { 411,1}};
static const map<PdgId,unsigned int> & mode2 = { { 2212,1},{-3122,1}, {-413,1}};
static const map<PdgId,unsigned int> & mode2CC = { {-2212,1},{ 3122,1}, { 413,1}};
DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
// loop over particles
for(unsigned int ix=0;ix<B0.decaying().size();++ix) {
_nB->fill();
int sign = 1, imode = 0;
if (B0.decaying()[ix].pid()>0 && B0.modeMatches(ix,3,mode1)) {
imode=0;
sign=1;
}
else if (B0.decaying()[ix].pid()<0 && B0.modeMatches(ix,3,mode1CC)) {
imode=0;
sign=-1;
}
else if (B0.decaying()[ix].pid()>0 && B0.modeMatches(ix,3,mode2)) {
imode=1;
sign=1;
}
else if (B0.decaying()[ix].pid()<0 && B0.modeMatches(ix,3,mode2CC)) {
imode=1;
sign=-1;
}
else
continue;
int iD = imode==0 ? 411 : 413;
const Particle & pp = B0.decayProducts()[ix].at( sign*2212)[0];
const Particle & lam = B0.decayProducts()[ix].at(-sign*3122)[0];
const Particle & Dm = B0.decayProducts()[ix].at(-sign*iD )[0];
_h[0][imode]->fill((lam.momentum()+pp.momentum()).mass());
// first boost to B rest frame
LorentzTransform boostB = LorentzTransform::mkFrameTransformFromBeta(B0.decaying()[ix].momentum().betaVec());
FourMomentum ppp = boostB.transform(pp .momentum());
FourMomentum plam = boostB.transform(lam.momentum());
FourMomentum pDm = boostB.transform(Dm .momentum());
LorentzTransform boostpLam = LorentzTransform::mkFrameTransformFromBeta((ppp+plam).betaVec());
ppp = boostpLam.transform(ppp);
pDm = boostpLam.transform(pDm);
_h[1][imode]->fill(ppp.p3().unit().dot(pDm.p3().unit()));
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<2;++ix) {
double fact = ix==0 ? 1e3 : 1e6;
for(unsigned int iy=0;iy<2;++iy) {
scale(_h[ix][iy], fact/ *_nB);
}
}
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[2][2];
CounterPtr _nB;
/// @}
};
RIVET_DECLARE_PLUGIN(BELLE_2015_I1392799);
}
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