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#include "SuepDecay.h"
SuepDecay::SuepDecay(const edm::ParameterSet& iConfig)
: idMediator_(iConfig.getParameter<int>("idMediator")),
idDark_(iConfig.getParameter<int>("idDark")),
temperature_(iConfig.getParameter<double>("temperature")) {}
bool SuepDecay::initAfterBeams() {
mDark_ = particleDataPtr->m0(idDark_);
bool medDecay = particleDataPtr->mayDecay(idMediator_);
if (!medDecay) {
loggerPtr->errorMsg("SuepDecay::initAfterBeams", "mediator decay should be enabled");
return false;
}
//construct the shower helper
suep_shower_ = std::make_unique<SuepShower>(mDark_, temperature_, rndmPtr);
return true;
}
//based on https://gitlab.com/simonknapen/suep_generator/-/blob/master/suep_main.cc:AttachSuepShower
bool SuepDecay::doVetoProcessLevel(Pythia8::Event& event) {
Pythia8::Vec4 pMediator, pDark;
// Find the mediator in the event
for (int i = 0; i < event.size(); ++i) {
//mediator w/ distinct daughters = last copy (decayed)
if (event[i].id() == idMediator_ && event[i].daughter1() != event[i].daughter2() && event[i].daughter1() > 0 &&
event[i].daughter2() > 0) {
pMediator = event[i].p();
// undo mediator decay
event[i].undoDecay();
// Generate the shower, output are 4 vectors in the rest frame of the shower, adding energy here avoids issues if scalar is off-shell
std::vector<Pythia8::Vec4> suep_shower_fourmomenta = suep_shower_->generateShower(pMediator.mCalc());
// Loop over hidden sector mesons and append to the event
int firstDaughter = event.size();
for (auto& pDark : suep_shower_fourmomenta) {
// Boost to the lab frame, i.e. apply the mediator boost
pDark.bst(pMediator);
// Append particle to the event w/ hidden meson pdg code. Magic number 91 means it is produced as a normal decay product
event.append(idDark_, 91, i, 0, 0, 0, 0, 0, pDark.px(), pDark.py(), pDark.pz(), pDark.e(), mDark_);
}
// Change the status code of the mediator to reflect that it has decayed.
event[i].statusNeg();
//set daughters of the mediator: daughter1 < daughter2 > 0 -> the particle has a range of decay products from daughter1 to daughter2
event[i].daughters(firstDaughter, event.size() - 1);
break;
}
}
//allow event to continue
return false;
}
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