Sum of two object phydics

ATLAS Software
#1

Hello Expert,

Sorry for the naive question!
I have two object physics one from the TruthMET and the other one is from the truth particle (dark photon).
I would like to add the dark photon to the missing energy transverse.

I tried with TLorentzVector But I have got the wrong result.
please find below part of my code:
for(const auto& MET : *truth_MET) {
MET_4vec.SetPtEtaPhiE(MET->mpx(), MET->mpy(), 0, MET->met());
}
for (const auto * tp : *truthPC){
…
…
Darkphoton_mom.SetPtEtaPhiE(tp->px(), tp->py(), tp->pz(), tp->pt());
}
MET_4vec += Darkphoton_mom;
Sum_MET_Dark = MET_4vec.Pt();

Can someone help me if my method is right or there is another way to compute this addition?

Your help is very appreciated!

Cheers,

S.Batlamous

#2

You could also ask this question on the root forum but the problem is that you’re setting the variables wrong: SetPtEtaPhiE expects to get x.Pt(), x.Eta(), x.Phi(), x.E(). There’s another function that sets things like you’re asking.

That being said, if you’re only asking for p_{\rm T} maybe it’s better to use TVector2.