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Rivet analyses reference
BELLE_2018_I1663447
Mass and angular distributions in $B^+\to K^+\eta\gamma$ decays
Experiment: BELLE (KEKB)
Inspire ID: 1663447
Status: VALIDATED NOHEPDATA
Authors:
References:
- Phys.Rev.D 97 (2018) 9, 092003
Beams: * *
Beam energies: ANY
Run details:
- Any process producing B+, originally Upsilno(4S) decay
Mass and angular distributions in $B^+\to K^+\eta\gamma$ decays. Data were read from the plots in the paper, but are background subtracted and efficiency corrected.
Source code:
BELLE_2018_I1663447.cc
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90 | // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief B+ -> K+ eta gamma
class BELLE_2018_I1663447 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2018_I1663447);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
UnstableParticles ufs = UnstableParticles(Cuts::abspid==521);
declare(ufs, "UFS");
DecayedParticles BP(ufs);
BP.addStable(PID::ETA);
declare(BP, "BP");
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);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const map<PdgId,unsigned int> & mode = { { 221,1},{ 321,1}, {22,1}};
static const map<PdgId,unsigned int> & modeCC = { { 221,1},{-321,1}, {22,1}};
DecayedParticles BP = apply<DecayedParticles>(event, "BP");
// loop over particles
for(unsigned int ix=0;ix<BP.decaying().size();++ix) {
int sign = 1;
if (BP.decaying()[ix].pid()>0 && BP.modeMatches(ix,3,mode)) {
sign=1;
}
else if (BP.decaying()[ix].pid()<0 && BP.modeMatches(ix,3,modeCC)) {
sign=-1;
}
else
continue;
const Particle & Kp = BP.decayProducts()[ix].at( sign*321)[0];
const Particle & eta = BP.decayProducts()[ix].at( 221)[0];
const Particle & gamma = BP.decayProducts()[ix].at( 22)[0];
FourMomentum pKeta = Kp.momentum()+eta.momentum();
double mass = pKeta.mass();
LorentzTransform boostB = LorentzTransform::mkFrameTransformFromBeta(BP.decaying()[ix].momentum().betaVec());
pKeta = boostB.transform(pKeta);
LorentzTransform boostKeta = LorentzTransform::mkFrameTransformFromBeta(pKeta.betaVec());
FourMomentum pK = boostKeta.transform(boostB.transform(Kp .momentum()));
FourMomentum pGamma = boostB.transform(gamma.momentum());
double cTheta = pK.p3().unit().dot(pGamma.p3().unit());
for(unsigned int iy=0;iy<2;++iy) {
_h[0][iy]->fill(cTheta);
_h[1][iy]->fill(mass );
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
for(unsigned int ix=0;ix<2;++ix)
for(unsigned int iy=0;iy<2;++iy)
normalize(_h[ix][iy],1.,false);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[2][2];
/// @}
};
RIVET_DECLARE_PLUGIN(BELLE_2018_I1663447);
}
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