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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
namespace Rivet {
/// @brief Study of ordered hadron chains at 7 TeV
class ATLAS_2017_I1624693 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2017_I1624693);
/// @name Analysis methods
//@{
struct usedX {
int locMin;
int locMax;
std::vector<std::pair<int,float> > chains;
// Constructor
usedX(int min, int max, int ic, float mass) {
locMin=min;
locMax=max;
chains.clear();
chains.push_back(std::pair<int,float>(ic,mass));
}
// Constructor
usedX(int min, int max) {
locMin=min;
locMax=max;
chains.clear();
}
void add(int jc, float mass) {
if (chains.size()) {
std::vector<std::pair<int,float> >::iterator it=chains.begin();
while ( it!=chains.end() && mass>(*it).second ) ++it;
chains.insert(it,std::pair<int,float>(jc,mass));
}
else {
chains.push_back(std::pair<int,float>(jc,mass));
}
}
};
/// Book histograms and initialise projections before the run
void init() {
/// @todo Initialise and register projections here
ChargedFinalState cfs((Cuts::etaIn(-2.5, 2.5) && Cuts::pT >= 0.1*GeV));
declare(cfs,"CFS");
// pion mass;
pim = 0.1396;
/// @todo Book histograms here, e.g.:
book(_DeltaQ , 1, 1, 1);
book(_Delta3h, 2, 1, 1);
book(_dalitz , 3, 1, 1);
// auxiliary
book(_h_nch, "_nch", 200, -0.5, 199.5);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
//const double weight = event.weight();
bool match =false;
/// @todo Do the event by event analysis here
const ChargedFinalState& had = applyProjection<ChargedFinalState>(event, "CFS");
Particles hs=had.particles();
int nch = hs.size();
if (nch < 3) return;
_h_nch->fill(1.*nch,1.);
for (unsigned int i=0; i < hs.size() - 1; ++i) {
for (unsigned int j=i+1; j < hs.size(); ++j) {
double q12 = qq(hs[i],hs[j],match);
if (match) _DeltaQ->fill(q12,-1.);
else _DeltaQ->fill(q12,1.);
}
}
// chain selection
std::vector<float> wchain;
std::vector< std::vector<unsigned int> > rchains;
std::vector< std::vector<float> > mchains;
wchain.clear(); rchains.clear(); mchains.clear();
for (unsigned int ip1 = 0; ip1< hs.size(); ++ip1 ) {
wchain.push_back(1.);
std::vector<unsigned int> cc(1,ip1);
std::vector<float> mc;
double qlmin=10000.; int ilmin=-1;
for (unsigned ip2 = 0; ip2 < hs.size(); ++ip2) {
if (ip2==ip1) continue;
double ql = qq(hs[ip1],hs[ip2],match);
if (!match) continue; // looking for closest like-sign match
if (ql <qlmin) { qlmin=ql; ilmin=ip2;}
}
if (ilmin<0) {
wchain.back()=0.;
mc.push_back(-1.);
}
else { // search for unlike-sign match
cc.push_back(ilmin);
mc.push_back(qlmin);
if (int(ip1)>ilmin && rchains[ilmin][1]==ip1) {
// std::cout <<"exclusive match:"<< std::endl;
wchain.back()=0.5; wchain[ilmin]=0.5;
}
double m3min=10000.; int ixmin=-1;
for (unsigned ip2 = 0; ip2< hs.size(); ++ip2) {
if (ip2==ip1 || int(ip2)==ilmin ) continue;
double qx = qq(hs[ip1],hs[ip2],match);
if (match) continue;
double qxl = qq(hs[ip2],hs[ilmin],match);
double m3 = sqrt(9*pim*pim+qxl*qxl+qlmin*qlmin+qx*qx);
if (m3 <m3min) { m3min=m3; ixmin=ip2;}
}
if (ixmin<0) {
wchain.back()=0.;
mc.push_back(-1.);
}
else {
cc.push_back(ixmin);
mc.push_back(m3min);
}
}
rchains.push_back(cc);
mchains.push_back(mc);
}
// cleanup: association rate for like-sign pairs should not exceed 2
std::vector<float> assoc(hs.size(),0.); // cache for association rate
std::vector<bool> accept(rchains.size(), false);
// loop over chains and accept lowest masses while watching the association rate
int inext = 0;
while ( inext>-1 ) {
inext = -1; float cMin = 100000.;
// find non-accepted chain with lowest Q_ls; dissolve chains if association count over 2
for (unsigned int ic=0; ic < rchains.size(); ++ic) {
if (rchains[ic].size() < 2) continue;
if (accept[ic]) continue;
if (mchains[ic][0] < cMin) { cMin = mchains[ic][0]; inext=ic; }
}
if (inext>-1 ) {
unsigned int cloc0 = rchains[inext][0];
unsigned int cloc1 = rchains[inext][1];
if ( (assoc[cloc0] + 1. <= 2.) && (assoc[cloc1] + 1. <= 2.) ) { // chain can be accepted
accept[inext]=true;
assoc[cloc0]+=1.;
assoc[cloc1]+=1.;
if (wchain[inext]==0.5) { // accept the identical chain, too
for (unsigned int ic=0; ic<hs.size(); ++ic) {
if (rchains[ic][0] == cloc1 && rchains[ic][1] == cloc0) {
accept[ic]=true;
break;
}
}
}
}
else if ( assoc[cloc0]>1 ) { // association count filled up, discard chain
accept[inext]=true;
wchain[inext]=0.;
}
else { // dissolve chain and find new association
unsigned int i1 = rchains[inext][0];
float mMn = 1000000.;
int ipn = -1;
for (unsigned int i2=0; i2<hs.size(); ++i2) {
if (i1 == i2) continue;
double m = qq(hs[i1],hs[i2],match);
if (!match) continue;
if (assoc[i2] > 1.) continue;
if (m > 0. && m <mMn ) { mMn = m; ipn = i2;}
}
if (ipn >= 0) {
rchains[inext][1]=ipn; mchains[inext][0]=mMn;
// resolve chain weight : by default, it is 1.
wchain[inext]=1.;
// check exclusivity of pairing
for (unsigned int ico=0; ico<hs.size(); ++ico) {
if (int(rchains[ico][0]) == ipn && rchains[ico][1] == i1) { // scale the contribution from both chains
wchain[ico]=0.5;
wchain[inext]=0.5;
}
}
// add 3.member
// continue with arbitrary match
int ipnn=-1; float mMnn = 10000.;
mMn = 1000000.;
for (unsigned int ij=0; ij < hs.size(); ++ij) {
rchains[inext].resize(2);
float q02 = qq(hs[i1],hs[ij],match);
if (match>0.) continue;
float q12 = qq(hs[ipn],hs[ij],match);
double m3 = sqrt(9*pim*pim+q02*q02+mMn*mMn+q12*q12);
if (m3>0. && m3 <mMnn ) { mMnn = m3; ipnn = ij; }
}
if (ipnn>=0) { rchains[inext].push_back(ipnn); rchains[inext][2]=ipnn; mchains[inext][1]=mMnn; }
else {accept[inext]=true; wchain[inext]=0.;}
}
else { // chain not recovered
wchain[inext]=0.;
accept[inext]=true;
}
}
}
} // end loop over chains
// cleanup: association rate for unlike-sign pairs
// third member verification
std::vector<bool> accept3(rchains.size(),false);
// watch unlike-sign combinations used
std::vector<usedX> used;
// loop over chains and accept lowest masses while watching the association rate
inext = 0;
while ( inext>-1 ) {
inext = -1; float cMin = 100000.;
// find non-accepted chain with lowest mass; dissolve chains if association count over 3
for (unsigned int ic=0; ic < rchains.size(); ++ic) {
if (rchains[ic].size() < 3 || !wchain[ic] || !accept[ic]) continue;
if (accept3[ic]) continue;
if (mchains[ic][1]<cMin) { cMin = mchains[ic][1]; inext=ic; }
}
// check association counts
if (inext>-1 ) {
unsigned int cloc0 = rchains[inext][0];
unsigned int cloc1 = rchains[inext][1];
unsigned int cloc2 = rchains[inext][2];
// map use of unlike sign pairs
int iu0 = -1; float w0=0.;
for (unsigned int iu=0; iu<used.size(); ++iu) {
if (fmin(cloc0,cloc2)==used[iu].locMin && fmax(cloc0,cloc2)==used[iu].locMax ) {
iu0=iu;
if (used[iu].chains.size() > 0)
for (unsigned int iw=0; iw<used[iu].chains.size(); ++iw) w0+=wchain[used[iu].chains[iw].first];
//used[iu].add(i1,mch[1]);
break;
}
}
if (iu0<0) { used.push_back(usedX(fmin(cloc0,cloc2),fmax(cloc0,cloc2)));iu0=used.size()-1; }
int iu1 = -1; float w1=0.;
for (unsigned int iu=0; iu<used.size(); ++iu) {
if (fmin(cloc1,cloc2)==used[iu].locMin && fmax(cloc1,cloc2)==used[iu].locMax) {
iu1=iu;
if (used[iu].chains.size()>0)
for (unsigned int iw=0; iw<used[iu].chains.size(); iw++) w1 += wchain[used[iu].chains[iw].first];
//used[iu].add(inext,mch[1]);
break;
}
}
if (iu1<0) { used.push_back(usedX(fmin(cloc1,cloc2),fmax(cloc1,cloc2))); iu1=used.size()-1; }
if ( assoc[cloc2] < 3. && w0 < 2. && w1 < 2.) {
accept3[inext] = true;
assoc[cloc2] += 1.;
used[iu0].add(inext, mchains[inext][1]);
used[iu1].add(inext, mchains[inext][1]);
if (wchain[inext]==0.5) { // accept the identical chain, too
for (unsigned int ic=0; ic< rchains.size(); ++ic) {
if (rchains[ic][0]==cloc1 && rchains[ic][1] == cloc0) {
accept3[ic]=true;
used[iu0].add(ic, mchains[ic][1]);
used[iu1].add(ic, mchains[ic][1]);
break;
}
}
}
}
else { // find new association
int i1 = rchains[inext][0];
int i2 = rchains[inext][1];
float mMn = 1000000.;
int ipn=-1; int iploc=-1;
rchains[inext].pop_back();
for (unsigned int i3 = 0; i3 < hs.size(); ++i3) {
double q02 = qq(hs[i1],hs[i3],match);
if (match > 0.) continue;
if (assoc[i3] > 3-wchain[inext]) continue;
// check pair association
w0=0.; w1=0.;
for (unsigned int iu=0; iu<used.size(); ++iu) {
if (fmin(cloc0,i3)==used[iu].locMin && fmax(cloc0,i3)==used[iu].locMax ) {
if (used[iu].chains.size() > 0)
for (unsigned int iw=0; iw<used[iu].chains.size(); ++iw) w0 += wchain[used[iu].chains[iw].first];
}
if (fmin(cloc1,i3)==used[iu].locMin && fmax(cloc1,i3)==used[iu].locMax ) {
if (used[iu].chains.size()>0)
for (unsigned int iw=0; iw<used[iu].chains.size(); ++iw) w1 += wchain[used[iu].chains[iw].first];
}
}
if (w0+wchain[inext]>2. || w1+wchain[inext]>2.) continue;
float q12 = qq(hs[i2],hs[i3],match);
float q01 = qq(hs[i1],hs[i2],match);
float m = sqrt(9*pim*pim+q02*q02+q01*q01+q12*q12);
if (m>0. && m <mMn ) { mMn = m; ipn = i3; iploc = i3; }
}
if (ipn>=0) {
rchains[inext].push_back(ipn); rchains[inext][2]=iploc; mchains[inext][1]=mMn;
}
else { // chain not recovered
wchain[inext]=0.;
}
}
}
} // end loop over chains
// end 3rd member optimization
for (unsigned int ip=0; ip < wchain.size(); ++ip) {
if (!wchain[ip]) continue;
if (rchains[ip].size() < 3) continue;
float m3min = mchains[ip][1];
if (m3min > 0.59) continue;
// dalitz plot
std::pair<float,float> dd = dalitz3(hs[rchains[ip][0]], hs[rchains[ip][1]], hs[rchains[ip][2]]);
_dalitz->fill(dd.first,dd.second,1.*wchain[ip]);
// Delta(Q) spectra
float qlmin = mchains[ip][0];
float qxmin = qq(hs[rchains[ip][0]], hs[rchains[ip][2]], match);
float xlmin = qq(hs[rchains[ip][1]], hs[rchains[ip][2]], match);
_Delta3h->fill(qxmin, 0.5*wchain[ip]);
_Delta3h->fill(xlmin, 0.5*wchain[ip]);
_Delta3h->fill(qlmin, -1.*wchain[ip]);
}
}
/// Normalise histograms etc., after the run
void finalize() {
// normalize by the number of charged particles
// counter automatic division by bin size
double norm = 0.01 / (_h_nch->xMean()*_h_nch->numEntries());
_dalitz->scaleW(norm);
_DeltaQ->scaleW(norm);
_Delta3h->scaleW(norm);
}
//@}
double qq(const Particle& gp1, const Particle& gp2, bool& match) {
match = gp1.charge() * gp2.charge() > 0;
FourMomentum p1, p2;
p1.setPM(gp1.px(), gp1.py(), gp1.pz(), pim);
p2.setPM(gp2.px(), gp2.py(), gp2.pz(), pim);
return sqrt(fmax(0., (p1 + p2).mass2() - 4*pim*pim));
}
std::pair<float,float> dalitz3(const Particle& gp1, const Particle& gp2, const Particle& gp3) const {
float p1= gp1.pt();
float p2= gp2.pt();
float p3= gp3.pt();
float th1 = gp1.theta();
float th2 = gp2.theta();
float th3 = gp3.theta();
float ph1 = gp1.phi();
float ph2 = gp2.phi();
float ph3 = gp3.phi();
float e1 = sqrt(p1*p1+pim*pim);
float e2 = sqrt(p2*p2+pim*pim);
float e3 = sqrt(p3*p3+pim*pim);
float p1x = p1*cos(ph1)*sin(th1);
float p1y = p1*sin(ph1)*sin(th1);
float p1z = p1*cos(th1);
float p2x = p2*cos(ph2)*sin(th2);
float p2y = p2*sin(ph2)*sin(th2);
float p2z = p2*cos(th2);
float p3x = p3*cos(ph3)*sin(th3);
float p3y = p3*sin(ph3)*sin(th3);
float p3z = p3*cos(th3);
float px = p1x+p2x+p3x;
float py = p1y+p2y+p3y;
float pz = p1z+p2z+p3z;
float ap = sqrt(px*px+py*py+pz*pz);
float e=e1+e2+e3;
float beta = ap/e;
float gamma = 1./sqrt(1-beta*beta);
float p1l = (p1x*px+p1y*py+p1z*pz)/ap;
float p2l = (p2x*px+p2y*py+p2z*pz)/ap;
float p3l = (p3x*px+p3y*py+p3z*pz)/ap;
float e1_boost = gamma*e1-gamma*beta*p1l;
float e2_boost = gamma*e2-gamma*beta*p2l;
float e3_boost = gamma*e3-gamma*beta*p3l;
float Q = sqrt(e*e-ap*ap)-3*pim;
return std::pair<float,float>(sqrt(3.)*(e1_boost-e2_boost)/Q , 3*(e3_boost-pim)/Q-1.);
}
private:
// Data members like post-cuts event weight counters go here
float pim;
private:
/// @name Histograms
Histo1DPtr _DeltaQ;
Histo1DPtr _Delta3h;
Histo1DPtr _h_nch;
Histo2DPtr _dalitz;
//@}
};
// This global object acts as a hook for the plugin system
RIVET_DECLARE_PLUGIN(ATLAS_2017_I1624693);
}
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