Daughter Particles Information in Full Simulation

lia · August 7, 2024, 2:59am

Dear All,

I am currently working on Full Simulation and have generated ee-->WW-->munumunu events. I would like to verify the truth information to ensure that the W bosons have decayed correctly into muon-neutrino pairs.

In the past, I used the Particle collection and Particle#1 to obtain the daughters’ information. However, in my recent simulations, these collections are absent in the ROOT file after reconstruction. I believe this change is due to an update in the edm4hep version. I can still find the MCParticle collection.

The simulated events are located here:
/eos/experiment/fcc/ee/analyses_storage/Higgs_and_TOP/HiggsInvisible/lia/generation/FullSimulation/CLD_reco/wzp6_ee_WW_munumunu_ecm240

Could you please guide me on which branch or collection now contains the daughter particles’ information similar to the previous Particle collection?

Thank you for your assistance.

Best regards,

Ang

jsmiesko · August 7, 2024, 11:51am

Hi @lia,

The # symbols were removed at some point from podio/EDM4hep to make the branches more easily readable. The Particle#1 should be equivalent to _MCParticles_daughters or _MCParticles_daughters.index.

Also, can you point me to the analyzer you are using?

Best,
Juraj

lia · August 7, 2024, 4:35pm

Hi @jsmiesko,

Yes, I am using MCParticles and _MCParticles_daughters.index. Here is the stage1 analyzer I am using:

github.com

Ang-Li-93/FCCWorkplace/blob/ab36d3a21406ca6b55fe18d42ed75200228a2a66/analysis/HiggsInvisible/FullSim_Validation/mumu/analysis_stage1.py#L190


      
          .Define("pdgID", "MCParticle::get_pdg(status2)")
          .Define("W_MC",  "MCParticle::sel_pdgID( 24, true) ( status2 )")
          .Define("W_MC_GenID", "MCParticle::get_genStatus(W_MC)")  
          .Define("W_MC_tlv", "MCParticle::get_tlv( W_MC )")
          .Define("W_MC_no", "W_MC.size()")
          .Define("W_MC_m", "MCParticle::get_mass(W_MC)")
          .Define("W_MC_p", "MCParticle::get_p(W_MC)") 
          #.Define("W_MC_daughters", "MCParticle::list_of_stable_particles_from_decay(W_MC, MCParticles, Particle1)")
          
          
          .Define("Wp_MC", "HiggsTools::gen_sel_pdgIDInt(24,false)(MCParticles)")
          .Define("Wp_MC_no", "Wp_MC.size()")
          .Define("daughter_Wp", "HiggsTools::gen_decay_list(Wp_MC, MCParticles, Particle1)")
          .Define("daughter_Wp_no", "daughter_Wp.size()")
          .Define("daughter_Wp_0_pid", "daughter_Wp.size()>0 ? daughter_Wp[0] : -1000")
          .Define("daughter_Wp_1_pid", "daughter_Wp.size()>1 ? daughter_Wp[1] : -1000")
          
          .Define("Wm_MC", "HiggsTools::gen_sel_pdgIDInt(-24,false)(status2)")
          .Define("Wm_MC_no", "Wm_MC.size()")
          .Define("daughter_Wm", "HiggsTools::gen_decay_list(Wm_MC, MCParticles, Particle1)")
          .Define("daughter_Wm_no", "daughter_Wm.size()")

The function HiggsTools::gen_decay_list can be found here:

github.com

Ang-Li-93/FCCAnalyses/blob/8f1abf19f7b1ab21be9e2c1c931905a742047074/analyzers/dataframe/src/HiggsTools.cc#L862


      
              int mc_index = FCCAnalyses::ReconstructedParticle2MC::getTrack2MC_index(track_index, recind, mcind, reco);
              if(mc_index >= 0 && mc_index < (int)mc.size()) {
                TLorentzVector mc_;
                mc_.SetXYZM(mc.at(mc_index).momentum.x, mc.at(mc_index).momentum.y, mc.at(mc_index).momentum.z, mc.at(mc_index).mass);
                if(mc_.P() > 20) result.push_back(reco_.P()/mc_.P());
              }
            } 
            return result;
          }
          
          std::vector<int> HiggsTools::gen_decay_list(ROOT::VecOps::RVec<int> mcin, ROOT::VecOps::RVec<edm4hep::MCParticleData> in, ROOT::VecOps::RVec<int> ind) {
          
            std::vector<int> result;
          
          
            // i = index of a MC particle in the Particle block
            // in = the Particle collection
            // ind = the block with the indices for the daughters, Particle#1.index
            
            // returns a vector with the indices (in the Particle block) of the daughters of the particle i

I am currently using MCParticles for Wp and status2 for Wm as a test, and I have the following output plots:

I believe I should be using MCParticles for the function HiggsTools::gen_decay_list as the second input parameter, but I am still confused as to why status2 is not working.

Thank you,
Ang

jsmiesko · August 9, 2024, 4:04pm

Hi @lia,

Can you try changing this line:

.Define("daughter_Wm", "HiggsTools::gen_decay_list(Wm_MC, MCParticles, Particle1)")

into this

.Define("daughter_Wm", "HiggsTools::gen_decay_list(Wm_MC, status2, Particle1)")

I believe that if you use status2 column in the HiggsTools::gen_sel_pdgIDInt()() the column Wm_MC will contain indexes in the status2 collection not in MCParticles collection.

Best,
Juraj

lia · August 14, 2024, 1:56pm

Hi @jsmiesko ,

Thank you so much, it works perfectly for me now,

Best,
Ang