Rivet analyses
Monte Carlo validation observables for heavy-flavour decays
Experiment: ()
Status: VALIDATED
Authors: - Francesco Curcio - Christian Gutschow
References: none listed
Beams: * *
Beam energies: ANY
Run details: - Anything with heavy-flavour jets
Jets with p⟂ > 25 GeV are constructed with an anti-k⟂ jet finder with R = 0.4 and projected onto many different observables sensitive to the decays of b- and c-hadrons in the heavy-flavour-tagged jet.
Source
code:MC_HFDECAYS.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/HeavyHadrons.hh"
namespace Rivet {
class MC_HFDECAYS : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(MC_HFDECAYS);
const string whoDis(const int pid) const {
switch (pid) {
case PID::B0: return "B0";
case PID::BPLUS: return "BPLUS";
case PID::B0S: return "B0S";
case PID::LAMBDAB: return "LAMBDAB";
case PID::D0: return "D0";
case PID::DPLUS: return "DPLUS";
case PID::DSPLUS: return "DSPLUS";
case PID::LAMBDACPLUS: return "LAMBDACPLUS";
default: return "";
}
}
/// Book histograms and initialise projections before the run
void init() {
declare(HeavyHadrons(),"HA");
FastJets jetpro(FinalState(), JetAlg::ANTIKT, 0.4, JetMuons::DECAY, JetInvisibles::DECAY);
declare(jetpro, "Jets");
// bar charts
book(_h["bar_b_jet_width"], "width_B_jet", 7, 0., 0.3);
book(_h["bar_c_jet_width"], "width_C_jet", 7, 0., 0.3);
// profiles
book(_p["b_jet_rho"], "avg_rho_B_jet", 10, 0., 0.4);
book(_p["c_jet_rho"], "avg_rho_C_jet", 10, 0., 0.4);
book(_p["b_jet_psi"], "avg_psi_B_jet", 10, 0., 0.4);
book(_p["c_jet_psi"], "avg_psi_C_jet", 10, 0., 0.4);
// histograms
book(_h["b_frac"], "prod_frac_B", 11, 0.5,11.5);
book(_h["c_frac"], "prod_frac_C", 7, 0.5, 7.5);
book(_h["b_jet_frag"], "frag_B_jet", 50, 0., 1.1);
book(_h["c_jet_frag"], "frag_C_jet", 50, 0., 1.1);
book(_h["b_jet_pT"], "pT_B_jet", 25, 25., 1025.);
book(_h["c_jet_pT"], "pT_C_jet", 25, 25., 1025.);
book(_h["b_jet_pThad"], "pThad_B_jet", 10, 0., 200.);
book(_h["c_jet_pThad"], "pThad_C_jet", 10, 0., 200.);
book(_h["b_jet_high_pT"], "high_pT_frag_B_jet", 46, 0., 1.);
book(_h["c_jet_high_pT"], "high_pT_frag_C_jet", 46, 0., 1.);
book(_h["b_jet_high_pT_1H"], "high_pT_frag_B_jet_1H", 46, 0., 1.);
book(_h["c_jet_high_pT_1H"], "high_pT_frag_C_jet_1H", 46, 0., 1.);
book(_h["ch_B0" ], "B0_charged_mult", 30, 0.5, 30.5);
book(_h["ch_BPLUS" ], "BPLUS_charged_mult", 30, 0.5, 30.5);
book(_h["ch_B0S" ], "B0S_charged_mult", 30, 0.5, 30.5);
book(_h["ch_LAMBDAB" ], "LAMBDAB_charged_mult", 30, 0.5, 30.5);
book(_h["ch_D0" ], "D0_charged_mult", 16, 0.5, 16.5);
book(_h["ch_DPLUS" ], "DPLUS_charged_multh", 16, 0.5, 16.5);
book(_h["ch_DSPLUS" ], "DSPLUS_charged_mult", 16, 0.5, 16.5);
book(_h["ch_LAMBDACPLUS"], "LAMBDACPLUS_charged_mult", 16, 0.5, 16.5);
book(_h["st_B0" ], "B0_stable_mult", 40, 0.5, 40.5);
book(_h["st_BPLUS" ], "BPLUS_stable_mult", 40, 0.5, 40.5);
book(_h["st_B0S" ], "B0S_stable_mult", 40, 0.5, 40.5);
book(_h["st_LAMBDAB" ], "LAMBDAB_stable_mult", 40, 0.5, 40.5);
book(_h["st_D0" ], "D0_stable_mult", 20, 0.5, 20.5);
book(_h["st_DPLUS" ], "DPLUS_stable_mult", 20, 0.5, 20.5);
book(_h["st_DSPLUS" ], "DSPLUS_stable_mult", 20, 0.5, 20.5);
book(_h["st_LAMBDACPLUS"], "LAMBDACPLUS_stable_mult", 20, 0.5, 20.5);
book(_h["pt_B0" ], "B0_pT", 10, 25., 425.);
book(_h["pt_BPLUS" ], "BPLUS_pT", 10, 25., 425.);
book(_h["pt_B0S" ], "B0S_pT", 10, 25., 425.);
book(_h["pt_LAMBDAB" ], "LAMBDAB_pT", 10, 25., 425.);
book(_h["pt_D0" ], "D0_pT", 10, 25., 425.);
book(_h["pt_DPLUS" ], "DPLUS_pT", 10, 25., 425.);
book(_h["pt_DSPLUS" ], "DSPLUS_pT", 10, 25., 425.);
book(_h["pt_LAMBDACPLUS"], "LAMBDACPLUS_pT", 10, 25., 425.);
book(_h["b_jet_ch_mult"], "charged_mult_B_jets", 40, 0.5, 40.5);
book(_h["c_jet_ch_mult"], "charged_mult_C_jets", 40, 0.5, 40.5);
book(_h["b_jet_l_pTrel"], "lepton_pTrel_B_jets", 8, 0., 15.);
book(_h["c_jet_l_pTrel"], "lepton_pTrel_C_jets", 8, 0., 10.);
book(_h["b_jet_l_pT"], "lepton_pT_B_jets", 10, 0., 100.);
book(_h["c_jet_l_pT"], "lepton_pT_C_jets", 10, 0., 100.);
// double-differentials
vector<double> groupEdges = ptaxis.edges(); // includes +/- inf
groupEdges.erase(groupEdges.begin()); groupEdges.pop_back(); // removes +/- inf
book(_g["avg_B_jet_ch_mult"], groupEdges);
book(_g["avg_C_jet_ch_mult"], groupEdges);
book(_g["avg_B_jet_l_pTrel"], groupEdges);
book(_g["avg_C_jet_l_pTrel"], groupEdges);
for (size_t i = 0; i < ptaxis.numBins(); ++i) {
const std::pair<double,double> ptbin = std::make_pair(ptaxis.min(i+1),ptaxis.max(i+1));
const string suff = to_string(int(ptbin.first)) + "_" + to_string(int(ptbin.second));
book(_p["avg_B_jet_rho_"+to_string(i)], "avg_B_jet_rho_"+suff, 10, 0., 0.4);
book(_p["avg_C_jet_rho_"+to_string(i)], "avg_C_jet_rho_"+suff, 10, 0., 0.4);
book(_g["avg_B_jet_ch_mult"]->bin(i+1), "avg_B_jet_ch_mult_"+suff, 40, 0.5, 40.5);
book(_g["avg_C_jet_ch_mult"]->bin(i+1), "avg_C_jet_ch_mult_"+suff, 40, 0.5, 40.5);
if (i == 0) {
book(_g["avg_B_jet_l_pTrel"]->bin(i+1), "avg_B_jet_l_pTrel_"+suff, 2, 0., 4.);
book(_g["avg_C_jet_l_pTrel"]->bin(i+1), "avg_C_jet_l_pTrel_"+suff, 2, 0., 3.);
}
else if (i <= 2) {
book(_g["avg_B_jet_l_pTrel"]->bin(i+1), "avg_B_jet_l_pTrel_"+suff, 4, 0., 8.);
book(_g["avg_C_jet_l_pTrel"]->bin(i+1), "avg_C_jet_l_pTrel_"+suff, 5, 0., 6.);
}
else {
book(_g["avg_B_jet_l_pTrel"]->bin(i+1), "avg_B_jet_l_pTrel_"+suff, 8, 0., 15.);
book(_g["avg_C_jet_l_pTrel"]->bin(i+1), "avg_C_jet_l_pTrel_"+suff, 8, 0., 10.);
}
}
}
double p_annulus(const Jet &jet, const double a, const double b) const {
// calculate the total momentum inside an annulus with a <= R < b
return sum(select(jet.particles(), [&](const Particle &p) {
const double dr = deltaR(p, jet);
return (dr < b && dr >= a);
}), Kin::pT, 0.)/GeV;
}
void count_mult(const Particle& p) {
unsigned int nst = p.stableDescendants().size() + 0.5;
unsigned int nch = p.stableDescendants(Cuts::charge != 0).size() + 0.5;
_h["st_"+whoDis(p.abspid())]->fill(nst);
_h["ch_"+whoDis(p.abspid())]->fill(nch);
}
double pTrel (const Jet& jet, const Particle& p) const {
return (p.p3().cross(jet.p3())).mod()/(jet.p3().mod());
}
/// Perform the per-event analysis
void analyze(const Event& event) {
const HeavyHadrons &ha = apply<HeavyHadrons>(event,"HA");
if (ha.bHadrons().empty() && ha.cHadrons().empty()) vetoEvent;
for (const Particle &p : ha.bHadrons()) {
const string name = "pt_" + whoDis(p.abspid());
if (p.abspid() == PID::B0) { //Take into consideration both particles and anti-particles with abs()
count_mult(p);
_h["b_frac"]->fill(1);
_h[name]->fill(p.pT()/GeV);
}
else if (p.abspid() == PID::BPLUS) {
count_mult(p);
_h["b_frac"]->fill(2);
_h[name]->fill(p.pT()/GeV);
}
else if (p.abspid() == PID::B0S) {
count_mult(p);
_h["b_frac"]->fill(3);
_h[name]->fill(p.pT()/GeV);
}
else if (p.abspid() == PID::BCPLUS) _h["b_frac"]->fill(4);
else if (p.abspid() == PID::LAMBDAB) {
count_mult(p);
_h["b_frac"]->fill(5);
_h[name]->fill(p.pT()/GeV);
}
else if (p.abspid() == PID::XIBMINUS) _h["b_frac"]->fill(6);
else if (p.abspid() == PID::XI0B) _h["b_frac"]->fill(7);
else if (p.abspid() == PID::OMEGABMINUS) _h["b_frac"]->fill(8);
else if (p.abspid() == PID::SIGMABMINUS) _h["b_frac"]->fill(9);
else if (p.abspid() == PID::SIGMAB) _h["b_frac"]->fill(10);
else if (p.abspid() == PID::SIGMABPLUS) _h["b_frac"]->fill(11);
}
for (const Particle &p : ha.cHadrons()) {
if( !p.fromBottom()){ //take into account only c-hadrons that don't come from a b-hadron decay
//Avoid double-counting b-hadron fractions
const string name = "pt_" + whoDis(p.abspid());
if (p.abspid() == PID::DPLUS) {
count_mult(p);
_h["c_frac"]->fill(1);
_h[name]->fill(p.pT()/GeV);
}
else if (p.abspid() == PID::D0) {
count_mult(p);
_h["c_frac"]->fill(2);
_h[name]->fill(p.pT()/GeV);
}
else if (p.abspid() == PID::DSPLUS) {
count_mult(p);
_h["c_frac"]->fill(3);
_h[name]->fill(p.pT()/GeV);
}
else if (p.abspid() == PID::LAMBDACPLUS) {
count_mult(p);
_h["c_frac"]->fill(4);
_h[name]->fill(p.pT()/GeV);
}
else if (p.abspid() == PID::XICPLUS) _h["c_frac"]->fill(5);
else if (p.abspid() == PID::XI0C) _h["c_frac"]->fill(6);
else if (p.abspid() == PID::OMEGA0C) _h["c_frac"]->fill(7);
}
}
Jets jets = apply<FastJets>(event, "Jets").jetsByPt(Cuts::pT > 25.*GeV && Cuts::absrap < 2.5);
if (jets.empty()) vetoEvent;
auto r_bins = _p["b_jet_rho"]->xEdges();
const double dr = r_bins[1]-r_bins[0]; //dr is equal for all bins
for (const Jet& thisJet : jets) {
double p_0_R = p_annulus(thisJet, 0., 0.4);
if (fuzzyEquals(p_0_R, 0., 1e-5)) continue;
Particles bjets = thisJet.bTags(Cuts::pT > 5*GeV);
iselect(bjets, deltaRLess(thisJet, 0.3));
for (const Particle &thisB : bjets) {
_h["b_jet_pThad"]->fill(thisB.pT()/GeV);
double z = thisJet.p3().dot(thisB.p3())/thisJet.p2();
_h["b_jet_frag"]->fill(z);
if (inRange(thisJet.pT(), 500*GeV, 1000*GeV)) {
_h["b_jet_high_pT"]->fill(z);
if (bjets.size() == 1) _h["b_jet_high_pT_1H"]->fill(z);
}
for (size_t i = 0; i < r_bins.size()-1; ++i) {
double r = 0.5*(r_bins[i]+r_bins[i+1]);
double rho = p_annulus(thisJet, r_bins[i], r_bins[i+1])/p_0_R/dr;
double psi = p_annulus(thisJet, 0, r_bins[i+1])/p_0_R;
_p["b_jet_rho"]->fill(r, rho);
_p["b_jet_psi"]->fill(r, psi);
size_t ptb = ptaxis.index(thisJet.pT()/GeV) - 1; // index in {1, nBins}
if (ptb < ptaxis.numBins()) _p["avg_B_jet_rho_"+to_string(ptb)]->fill(r, rho);
}
}
Particles cjets = thisJet.cTags(Cuts::pT > 5*GeV);
iselect(cjets, deltaRLess(thisJet, 0.3));
if (bjets.empty()) {
for (const Particle& thisC : cjets) {
_h["c_jet_pThad"]->fill(thisC.pT()/GeV);
double z = thisJet.p3().dot(thisC.p3())/thisJet.p2();
_h["c_jet_frag"]->fill(z);
if (inRange(thisJet.pT(), 500*GeV, 1000*GeV)) {
_h["c_jet_high_pT"]->fill(z);
if (cjets.size() == 1) {
_h["c_jet_high_pT_1H"]->fill(z);
}
}
for (size_t i = 0; i < r_bins.size()-1; ++i) {
double r = 0.5*(r_bins[i]+r_bins[i+1]);
double rho = p_annulus(thisJet, r_bins[i], r_bins[i+1])/p_0_R/dr;
double psi = p_annulus(thisJet, 0, r_bins[i+1])/p_0_R;
_p["c_jet_rho"]->fill(r, rho);
_p["c_jet_psi"]->fill(r, psi);
size_t ptb = ptaxis.index(thisJet.pT()/GeV) - 1; // index in {0, nBins - 1}
if (ptb < ptaxis.numBins()) _p["avg_C_jet_rho_"+to_string(ptb)]->fill(r, rho);
}
}
}
if (bjets.size()) {
double W_num = 0., W_den = 0.;
long N_charged = 0;
for (const Particle& pp : thisJet.particles()) {
if(pp.isStable()) {
W_num += pp.pT()*deltaR(thisJet,pp);
W_den += pp.pT();
if (pp.isCharged()) ++N_charged;
}
if(pp.isLepton()) {
_h["b_jet_l_pT"]->fill(pp.pT()/GeV);
_h["b_jet_l_pTrel"]->fill(pTrel(thisJet,pp)/GeV);
_g["avg_B_jet_l_pTrel"]->fill(thisJet.pT()/GeV, pTrel(thisJet,pp)/GeV);
}
}
if (W_den) _h["bar_b_jet_width"]->fill(W_num/W_den);
_h["b_jet_pT"]->fill(thisJet.pT()/GeV);
if (N_charged) {
_h["b_jet_ch_mult"]->fill(N_charged);
_g["avg_B_jet_ch_mult"]->fill(thisJet.pT()/GeV, (double)N_charged);
}
}
else if(cjets.size()) {
double W_num = 0., W_den = 0.;
long N_charged = 0;
for (const Particle& pp : thisJet.particles()) {
if(pp.isStable()) {
W_num += pp.pT()*deltaR(thisJet,pp);
W_den += pp.pT();
if(pp.isCharged()) ++N_charged;
}
if(pp.isLepton()) {
_h["c_jet_l_pT"]->fill(pp.pT()/GeV);
_h["c_jet_l_pTrel"]->fill(pTrel(thisJet,pp)/GeV);
_g["avg_C_jet_l_pTrel"]->fill(thisJet.pT()/GeV, pTrel(thisJet,pp)/GeV);
}
}
if (W_den) _h["bar_c_jet_width"]->fill(W_num/W_den);
_h["c_jet_pT"]->fill(thisJet.pT()/GeV);
if (N_charged) {
_h["c_jet_ch_mult"]->fill(N_charged);
_g["avg_C_jet_ch_mult"]->fill(thisJet.pT()/GeV, (double)N_charged);
}
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
for (const auto &hit : _h) {
double sf = 1.0;
if (hit.first.find("bar_") != string::npos) {
sf = (hit.second->xMax()-hit.second->xMin())/hit.second->numBins();
}
normalize(hit.second, sf);
}
normalize(_g);
}
private:
map<string, Histo1DPtr> _h;
map<string, Profile1DPtr> _p;
map<string, Histo1DGroupPtr> _g;
YODA::Axis<double> ptaxis{25, 30, 50, 70, 100, 150, 300, 500, 1000};
};
RIVET_DECLARE_PLUGIN(MC_HFDECAYS);
}