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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/UnstableParticles.hh"
#include "Rivet/Projections/Sphericity.hh"
namespace Rivet {
/// @brief D*+/- polarization at 29 GeV
class HRS_1987_I250823 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(HRS_1987_I250823);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
declare(Beam(), "Beams");
declare(Sphericity(FinalState()), "Sphericity");
declare(UnstableParticles(), "UFS" );
for(unsigned int i=0;i<9;++i) {
unsigned int ix(0),iy(1);
if(i<3) {
ix=1;
iy=i+1;
}
else if(i==3) {
ix=2;
}
else if(i<6) {
ix=3;
iy=i-3;
}
else {
ix=i-2;
}
book(_p_rho00[i],ix,iy,1);
book(_p_rho11[i],ix,iy,2);
book(_p_rho10[i],ix,iy,3);
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// Get beams and average beam momentum
const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
const double meanBeamMom = ( beams.first.p3().mod() +
beams.second.p3().mod() ) / 2.0;
MSG_DEBUG("Avg beam momentum = " << meanBeamMom);
Vector3 axis;
if(beams.first.pid()>0)
axis = beams.first .momentum().p3().unit();
else
axis = beams.second.momentum().p3().unit();
// sphericity, to define an axis
const Sphericity& sphericity = apply<Sphericity>(event, "Sphericity");
// loop over the particles
for(const Particle& p : apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid==413)) {
int sign = p.pid()/p.abspid();
Particle decay;
double xE = p.momentum().E()/meanBeamMom;
if(p.children()[0].pid()==sign*421 &&
p.children()[1].pid()==sign*211) {
decay = p.children()[1];
}
else if(p.children()[1].pid()==sign*421 &&
p.children()[0].pid()==sign*211) {
decay = p.children()[0];
}
else
continue;
// axis and ctheta
LorentzTransform boost = LorentzTransform::mkFrameTransformFromBeta(p.momentum().betaVec());
Vector3 e1z = p.p3().unit();
FourMomentum pp = boost.transform(decay.momentum());
Vector3 axis1 = boost.transform(decay.momentum()).p3().unit();
double ctheta = e1z.dot(axis1);
// y and z axis
Vector3 e1y = e1z.cross(axis).unit();
Vector3 e1x = e1y.cross(e1z).unit();
double phi = atan2(e1y.dot(axis1),e1x.dot(axis1));
double w1 = 0.5*(5.*sqr(ctheta)-1.);
double w2 = -1.25*(1.-sqr(ctheta))*cos(2.*phi);
double w3 = -1.25*sqrt(2)*ctheta*sqrt(1.-sqr(ctheta))*cos(phi);
// fill the hists by x_E
for(unsigned int ix=0;ix<6;++ix) {
_p_rho00[ix]->fill(xE,w1);
_p_rho11[ix]->fill(xE,w2);
_p_rho10[ix]->fill(xE,w3);
}
_p_rho00[6]->fill(1.,w1);
_p_rho11[6]->fill(1.,w2);
_p_rho10[6]->fill(1.,w3);
// using jet axis
double pT = sqrt(sqr(sphericity.sphericityMajorAxis().dot(p.momentum().p3()))+
sqr(sphericity.sphericityMinorAxis().dot(p.momentum().p3())));
Vector3 axis2;
if(p.momentum().p3().dot(sphericity.sphericityAxis())>=0.) {
axis2 = sphericity.sphericityAxis();
}
else {
axis2 =-sphericity.sphericityAxis();
}
Vector3 e2y = e1z.cross(axis2).unit();
Vector3 e2x = e2y.cross(e1z).unit();
// alpha and beta
phi = atan2(e2y.dot(axis1),e2x.dot(axis1));
w1 = 0.5*(5.*sqr(ctheta)-1.);
w2 = -1.25*(1.-sqr(ctheta))*cos(2.*phi);
w3 = -1.25*sqrt(2)*ctheta*sqrt(1.-sqr(ctheta))*cos(phi);
if(xE<0.4) continue;
_p_rho00[7]->fill(1.,w1);
_p_rho11[7]->fill(1.,w2);
_p_rho10[7]->fill(1.,w3);
if(pT<0.75) {
_p_rho00[7]->fill(2.,w1);
_p_rho11[7]->fill(2.,w2);
_p_rho10[7]->fill(2.,w3);
}
else {
_p_rho00[7]->fill(3.,w1);
_p_rho11[7]->fill(3.,w2);
_p_rho10[7]->fill(3.,w3);
}
if(sphericity.sphericity()>=0.1) {
_p_rho00[8]->fill(1.,w1);
_p_rho11[8]->fill(1.,w2);
_p_rho10[8]->fill(1.,w3);
}
else {
_p_rho00[8]->fill(2.,w1);
_p_rho11[8]->fill(2.,w2);
_p_rho10[8]->fill(2.,w3);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
}
//@}
/// @name Histograms
//@{
Profile1DPtr _p_rho00[9],_p_rho11[9],_p_rho10[9];
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(HRS_1987_I250823);
}
|