// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
namespace Rivet {
/// @brief B -> D semileptonic
class BELLE_2022_I2169621 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2022_I2169621);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// projection
declare(UnstableParticles(Cuts::pid==511 or
Cuts::pid==521), "UFS");
// histograms
for(unsigned int ix=0;ix<4;++ix)
book(_h[ix],1,1,1+ix);
for(unsigned int ix=0;ix<2;++ix)
book(_nB[ix],"TMP/nB_"+toString(ix));
}
// Check for explicit decay into pdgids
bool isSemileptonicDecay(const Particle& mother, vector<int> ids) {
// Trivial check to ignore any other decays but the one in question modulo photons
const Particles children = mother.children(Cuts::pid!=PID::PHOTON);
if (children.size()!=ids.size()) return false;
// Check for the explicit decay
return all(ids, [&](int i){return count(children, hasPID(i))==1;});
}
// Calculate the recoil w using mother and daugher meson
double recoilW(const Particle& B, int mesonID) {
// TODO why does that not work with const?
Particle D = filter_select(B.children(), Cuts::pid==mesonID)[0];
FourMomentum q = B.mom() - D.mom();
return (B.mom()*B.mom() + D.mom()*D.mom() - q*q )/ (2. * sqrt(B.mom()*B.mom()) * sqrt(D.mom()*D.mom()) );
}
/// Perform the per-event analysis
void analyze(const Event& event) {
for(const Particle & p : apply<UnstableParticles>(event, "UFS").particles()) {
if(p.children().size()<=1) continue;
if(p.pid()==PID::BPLUS) {
_nB[0]->fill();
if (isSemileptonicDecay(p, {PID::D0BAR,PID::POSITRON,PID::NU_E})) _h[0]->fill(recoilW(p, PID::D0BAR));
if (isSemileptonicDecay(p, {PID::D0BAR,PID::ANTIMUON,PID::NU_MU})) _h[1]->fill(recoilW(p, PID::D0BAR));
}
else if(p.pid()==PID::B0) {
_nB[1]->fill();
if (isSemileptonicDecay(p, {PID::DMINUS,PID::POSITRON,PID::NU_E})) _h[2]->fill(recoilW(p, PID::DMINUS));
if (isSemileptonicDecay(p, {PID::DMINUS,PID::ANTIMUON,PID::NU_MU})) _h[3]->fill(recoilW(p, PID::DMINUS));
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
double tau[2] = {1638e-15,1519e-15};
double hbar = 6.582119569e-10;
for(unsigned int ix=0;ix<4;++ix) {
double fact = ix<2 ? hbar/tau[0] : hbar/tau[1];
CounterPtr c = ix<2 ? _nB[0] : _nB[1];
scale(_h[ix],fact/ *c);
}
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h[4];
CounterPtr _nB[2];
/// @}
};
RIVET_DECLARE_PLUGIN(BELLE_2022_I2169621);
}