Rivet analyses
Mass distributions and helicity angles in B+ → K+π+π− and B+ → K+K+K−
Experiment: BELLE (KEKB)
Inspire ID: 667959
Status: VALIDATED NOHEPDATA
Authors: - Peter Richardson
References: - Phys.Rev.D 71 (2005) 092003
Beams: * *
Beam energies: ANY
Run details: - Any process producing B+ mesons, originally Upsilon(4S) decays
Measurement of Mass distributions and helicity angles in B+ → K+π+π− and B+ → K+K+K− decays. The data were read from the figures in the paper and the backgrounds given subtracted.
Source
code:BELLE_2005_I667959.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/DecayedParticles.hh"
namespace Rivet {
/// @brief B -> K pi pi K K K
class BELLE_2005_I667959 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2005_I667959);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
UnstableParticles ufs = UnstableParticles(Cuts::abspid==521);
declare(ufs, "UFS");
DecayedParticles BP(ufs);
BP.addStable(PID::PI0);
BP.addStable(PID::K0S);
BP.addStable(PID::ETA);
BP.addStable(PID::ETAPRIME);
declare(BP, "BP");
vector<double> bins = {0.,5.,10.,15.,20.,30.};
vector<double> bins2 = {0.,1.05,5.,10.,30.};
// histos
for (unsigned int ix=0; ix<2; ++ix) {
book(_h_mass3[ix], 2, 1, 1+ix);
book(_h_mass2[0][ix],bins);
if (ix==0) book(_h_mass2[1][ix],bins );
else book(_h_mass2[1][ix],bins2);
for(unsigned int iy=0; iy<3; ++iy) {
book(_h_mass[ix][iy],1+4*ix,1,1+iy);
if (iy==2) continue;
book(_h_mass_zoom[ix][iy],1+4*ix,2,1+iy);
}
for(unsigned int iz=0;iz<5;++iz) {
book(_h_mass2[0][ix]->bin(1+iz),3,1+ix,1+iz);
if (ix==1 &&iz==4) continue;
book(_h_mass2[1][ix]->bin(iz+1),6,1+ix,1+iz);
}
}
for (unsigned int ix=0;ix<3;++ix) {
vector<double> bins3;
if (ix==0) bins3 = {0.82,0.97,1.,1.76};
else if (ix==1) bins3 = {0.,0.9,1.06};
else if (ix==2) bins3 = {0.,1.05,3.0};
book(_h_angle[ix],bins3);
for (unsigned int iy=0; iy<2; ++iy) {
if (ix==0) book(_h_angle[ix]->bin(2*iy+1),4,1,1+iy);
else if (ix==1) book(_h_angle[ix]->bin(iy+1) ,4,1,3+iy);
else if (ix==2) book(_h_angle[ix]->bin(iy+1) ,7,1,1+iy);
}
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
static const double mD0 = 1.86484, mJpsi = 3.096916, mPsi2S=3.6861;
DecayedParticles BP = apply<DecayedParticles>(event, "BP");
// loop over particles
for (unsigned int ix=0; ix<BP.decaying().size(); ++ix) {
int sign=BP.decaying()[ix].pid()/BP.decaying()[ix].abspid();
// boost to B rest frame
LorentzTransform boost =
LorentzTransform::mkFrameTransformFromBeta(BP.decaying()[ix]. mom().betaVec());
if (BP.modeMatches(ix,3,mode1) || BP.modeMatches(ix,3,mode1CC)) {
const Particle & Kp = BP.decayProducts()[ix].at( sign*321)[0];
const Particle & pip = BP.decayProducts()[ix].at( sign*211)[0];
const Particle & pim = BP.decayProducts()[ix].at(-sign*211)[0];
FourMomentum pKpi = Kp.mom() +pim.mom();
double mKpi = pKpi.mass();
if (abs(mKpi -mD0)<0.1 ) continue;
FourMomentum ppipi = pip.mom()+pim.mom();
double mpipi = ppipi.mass();
if (abs(mpipi -mD0)<0.015 || abs(mpipi-mJpsi)<0.07 || abs(mpipi-mPsi2S)<0.05) continue;
_h_mass[0][0]->fill(mKpi);
_h_mass[0][1]->fill(mpipi);
_h_mass[0][2]->fill((Kp.mom()+pip.mom()).mass());
_h_mass_zoom[0][0]->fill(mKpi);
_h_mass_zoom[0][1]->fill(mpipi);
if (sqr(mpipi)<11.) _h_mass3[0]->fill(mKpi);
else _h_mass3[1]->fill(mKpi);
_h_mass2[0][0]->fill(sqr(mpipi),mKpi );
_h_mass2[0][1]->fill(sqr(mKpi ),mpipi);
// helicity angles
// Kpi
pKpi = boost.transform(pKpi);
LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pKpi.betaVec());
FourMomentum ppi = boost2.transform(boost.transform(pim.mom()));
const double cK = ppi.p3().unit().dot(pKpi.p3().unit());
_h_angle[0]->fill(mKpi,cK);
// pi pi
ppipi = boost.transform(ppipi);
LorentzTransform boost3 = LorentzTransform::mkFrameTransformFromBeta(ppipi.betaVec());
ppi = boost3.transform(boost.transform(pim.mom()));
const double cPi = ppi.p3().unit().dot(ppipi.p3().unit());
_h_angle[1]->fill(mpipi,cPi);
}
else if (BP.modeMatches(ix,3,mode2) || BP.modeMatches(ix,3,mode2CC)) {
const Particles& Kp = BP.decayProducts()[ix].at( sign*321);
const Particle & Km = BP.decayProducts()[ix].at(-sign*321)[0];
FourMomentum pKK[2] = {Kp[0].mom()+Km.mom(), Kp[1].mom()+Km.mom()};
double mKK[2] = {pKK[0].mass(),pKK[1].mass()};
if (mKK[0]>mKK[1]) {
swap(mKK[0],mKK[1]);
swap(pKK[0],pKK[1]);
}
_h_mass[1][0]->fill(mKK[0]);
_h_mass[1][1]->fill(mKK[1]);
_h_mass[1][2]->fill((Kp[0].mom()+Kp[1].mom()).mass());
_h_mass_zoom[1][0]->fill(mKK[0]);
_h_mass_zoom[1][1]->fill(mKK[1]);
_h_mass2[1][0]->fill(sqr(mKK[1]),mKK[0]);
_h_mass2[1][1]->fill(sqr(mKK[0]),mKK[1]);
// helicity angles
// Kpi
pKK[0] = boost.transform(pKK[0]);
LorentzTransform boost2 = LorentzTransform::mkFrameTransformFromBeta(pKK[0].betaVec());
FourMomentum pK = boost2.transform(boost.transform(Km.mom()));
double cK = pK.p3().unit().dot(pKK[0].p3().unit());
_h_angle[2]->fill(mKK[0],cK);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
for (unsigned int ix=0; ix<2; ++ix) {
normalize(_h_mass3[ix], 1.0, false);
normalize(_h_mass[ix], 1.0, false);
normalize(_h_mass_zoom[ix], 1.0, false);
normalize(_h_mass2[ix], 1.0, false);
}
normalize(_h_angle, 1.0, false);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _h_mass[2][3],_h_mass_zoom[2][2],_h_mass3[2];
Histo1DGroupPtr _h_mass2[2][2],_h_angle[3];
const map<PdgId,unsigned int> mode1 = { { 321,1}, { 211,1}, {-211,1} };
const map<PdgId,unsigned int> mode1CC = { {-321,1}, { 211,1}, {-211,1} };
const map<PdgId,unsigned int> mode2 = { { 321,2}, {-321,1} };
const map<PdgId,unsigned int> mode2CC = { {-321,2}, { 321,1} };
/// @}
};
RIVET_DECLARE_PLUGIN(BELLE_2005_I667959);
}