Rivet analyses
title: BELLE_2005_I667959
Mass distributions and helicity angles in $B^+\to K^+\pi^+\pi^-$ and $B^+\to K^+K^+K^-$
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 $B^+\to K^+\pi^+\pi^-$ and $B^+\to K^+K^+K^-$ decays. The data were read from the figures in the paper and the backgrounds given subtracted.
Source code:BELLE_2005_I667959.cc
```c++ // -- C++ --
include "Rivet/Analysis.hh"
include "Rivet/Projections/DecayedParticles.hh"
include "Rivet/Projections/UnstableParticles.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);
} ```