RJPsi analysis - Pisa

This page presents general information pertinent to the Pisa group regarding the R(J/psi) analysis in the leptonic channel performed by ETH and Pisa groups.

Organization and activity

The people involved in the analysis are: Shubhi Parolia, Alberto Messineo, Franco Ligabue, Fabrizio Palla, Gabriel Ramirez.

Other related meetings:

Topic related presentations:

  • Federica Riti (ETH) - R(J/psi) analysis. Leptonic channel - BPH Jamboree - 15.12.2020 - here
  • Gino Isidori - Theoretical form factor uncertainty - 6.7.2020 - https://indico.cern.ch/event/935680/
  • Pisa group - Q^2 resolution studies - 6.7.2020 - here
  • Gino Isidori - Notes on LFU tests in Bc -> J/psi l nu decays - 22.6.2020 - here
  • Pisa group - R(J/Psi) studies at Pisa - R(J/psi) WG meeting - 9.6.2020 - here
  • Pisa group - Muon Identification studies - 27.7.2020 - here

MC generation status

Jira ticket to increase 2018 sample priority https://its.cern.ch/jira/browse/HIGHPRIOREQ-209

  • inclusive Bc (this consists of three separate batches because of purely technical reasons)



  • inclusive Jpsi(mm) + X

  • Jpsi(mm) + mu


GDoc of ongoing task for the Pisa group:


Task Group Priority Status Details
Preselection cuts optimisation Pisa High Ongoing Shubhi is studing the implementation of a genetic algorithm to perform the optimisation
Event selection using NN (2 vs 3 classes) Both Medium Pending  
Regression I Pisa High Ongoing Plug into the new reconstruction
Regression II Pisa High Ongoing Check effect on backgrounds / discrimination (simple plots / roc curves?)
Background Studies: combinatorial background 1 Pisa High Pending Produce the distribution of the uncorrelated muon forming a Jpsi using SB distributions and comparison between them
Background Studies: combinatorial background 2 ETH High Pending Jpsi(mm) + mu -> from MC, use EvtGen to force decays; 3 mu → hard? Event mixing? But small?
Background Studies: fakes Pisa High Pending Check pi/K fake rates, Use Bc -> Jpsi pi to get a pure sample of pions in data, B+ -> jpsi K+ to get a pure sample kaons in data (maybe something different now?)
Muon id studies (soft, medium...) Pisa Medium Done To be redone to include: New reconstruction, full source of simulated background available and produce improved plots
Muon id efficiency computation Pisa Medium Pending?  
Studies on the vertex probability and 3D impact parameter Pisa Medium Ongoing Fabrizio worked on this and point out the utility of these variable for discrimination between the different contributions. Complement with samples reconstructed with the new code.
Definition of control regions ETH Medium   Possibly derive corrections
Form factor MC reweighing ETH Medium Ongoing Detailed info. Needs miniAOD inputs. May end up being an additional producer in the nanoAOD sequence. Riccardo working on the implementation at the moment
MC corrections   Low Pending ID & trigger: see if these SF can be recycled from BPH / MUON POG
Fit model: how to input mu and tau (free / prior?) ETH Medium Done assume PDG Jpsipi /Jspimunu BR and fit Jpsipi, taunu is free
Fit model: signal subtraction in sideband region ETH Medium Done  
Fit model: design a blinding strategy ETH Medium Done obfuscate tau normalisation using random number
Fit model: control region ETH Medium   tau-free, muon enriched to measure the muon BR
BParking   Low    
Other B hadron decays into Jpsi + mu I ETH Medium Ongoing New samples in the making
Other B hadron decays into Jpsi + mu II ETH Medium Done Check if Jpsi mm gamma is included in the sample. Yes, in the new MC
Other B hadron decays into Jpsi + mu III ETH Medium Done Check Bc decays in this MC (and remove if signal!) -> producing dedicated Bc MCs
Decide what reconstruction code to use Both Ultrahigh Done We decided to develop a version in between the two codes parting from ETH version
Decide on the PV to choose from the collection Pisa High Done  
Moved to CMSSW_10_6_X for UL Both Low Done  
Use 2016, 2017 and 2018 data? Both Low Pending Start from 2018 and then trickle down? -- 2018 > 2017 > 2016, 16 only if really needed

Details of the analysis

Latest ntuples

Sample Weighting factors 21May7
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/data_ptmax_merged.root N.A.
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar18/datalowmass_ptmax_merged.root N.A.
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/BcToJPsiMuMu_is_chic0_mu_merged.root 0.52
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/BcToJPsiMuMu_is_chic1_mu_merged.root 0.52
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/BcToJPsiMuMu_is_chic2_mu_merged.root 0.52
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/BcToJPsiMuMu_is_hc_mu_merged.root 0.52
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/BcToJPsiMuMu_is_jpsi_3pi_merged.root 0.52
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/BcToJPsiMuMu_is_jpsi_hc_merged.root 0.52
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/BcToJPsiMuMu_is_jpsi_mu_merged.root 0.52
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/BcToJPsiMuMu_is_jpsi_pi_merged.root 0.52
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/BcToJPsiMuMu_is_jpsi_tau_merged.root 0.52
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/BcToJPsiMuMu_is_psi2s_mu_merged.root 0.52
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/BcToJPsiMuMu_is_psi2s_tau_merged.root 0.52
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar15/HbToJPsiMuMu_ptmax_merged.root 6.7 (jpsi_x)
root://cms-xrd-global.cern.ch//store/user/friti/dataframes_2021Mar16/HbToJPsiMuMu3MuFilter_ptmax_merged.root 8.5 (jpsi_x_mu)

(Work in progress)

Selection of PV... Differences between UL and legacy...

Establish three categories for the study:

  • JPsi + Tk trigger.
  • Dimuon0 + muon trigger.
  • Both together.

General details:

Analysis workflow diagram can be found here. (Work in progress)

Trigger path used:

  • HLT_DoubleMu4_JpsiTrk_Displaced_v* : pT()>4 GeV; pT(Jpsi)>6.9 GeV; 2.9 < m(+-) < 3.3 GeV, a vertex CL >10% and Lxy/sigma(Lxy)>3 pT(tk)> 1.2 GeV and chi^2 (+-tk) vertex/ndof <10. Where stands for the muons coming from the Jpsi.
  • HLT_Dimuon0_Jpsi3p5_Muon2_v*: Requires three muons. pT()>2 GeV; pT(muons forming the Jpsi)>3.5 GeV; m(+-) between 2.9 and 3.3 GeV, and a vertex CL>0.5%. The HLT requires three muons in the CMS geometrical acceptance: two of these muons need to be oppositely charged and form a J/Psi candidate with pT > 3.5 GeV, invariant mass in the range 2.95 - 3.25 GeV and vertex probability larger than 0.5%; the third muon is required to have pT > 2.0 GeV.

Offline cuts: pT(mu) > 4 GeV; 2.95 < mass(J/Psi) < 3.25 GeV; Soft muons; pT(J/Psi) > 8 GeV

Code & samples

Running currently on UL samples.

  • Reconstruction here
  • Addition of puWeights here
  • Nano skimmer here

MC samples global tag: 106X_upgrade2018_realistic_v11_L1v1

Process DAS name DBS instance nevents gen. cuts & filtering comments
BcToJpsiTauNu* /BcToJPsiTauNu_TuneCP5_13TeV-bcvegpy2-pythia8-evtgen/RunIISummer19UL18MiniAOD-106X_upgrade2018_realistic_v11_L1v1_ext1-v2/MINIAODSIM prod/global 6187083    
BcToJpsiMuNu* /BcToJPsiMuNu_TuneCP5_13TeV-bcvegpy2-pythia8-evtgen/RunIISummer19UL18MiniAOD-106X_upgrade2018_realistic_v11_L1v1_ext1-v2/MINIAODSIM prod/global 7475467    
OniaX* /OniaAndX_ToMuMu_MuFilter_SoftQCDnonD_TuneCP5_13TeV-pythia8-evtgen/RunIIAutumn18MiniAOD-102X_upgrade2018_realistic_v15-v1/MINIAODSIM prod/global 93757093    
Bc mix private prod /store/user/manzoni/RJPsi Bc PMX HLT RECO MINI 28oct20 v5        
*Samples currently used and will be replaced soon with the central production coming up.

Data samples gloabl tag: 106X_dataRun2_v28 lumimask here

Sample DAS name nevents comments
Charmonium-Run2018A /Charmonium/Run2018A-12Nov2019_UL2018_rsb-v1/MINIAOD 93082605  
Charmonium-Run2018B /Charmonium/Run2018B-12Nov2019_UL2018-v1/MINIAOD 46847388  
Charmonium-Run2018C /Charmonium/Run2018C-12Nov2019_UL2018-v1/MINIAOD 35346793  
Charmonium-Run2018D /Charmonium/Run2018D-12Nov2019_UL2018-v1/MINIAOD 217135606  

Useful information

Old reconstruction code https://github.com/gabriel-rmrz/BcAnalysis.git

Process DAS name DBS instance nevents gen. cuts & filtering comments
Bc -> Jpsi tau nu (signal sample) /BcJpsiTauNu_020519/cgalloni-Fall18_10_2_9-MINIAODSIM_noDuplCheck_020519-092bfc61e82f18935ea11e32077a486f/USER prod/phys03 1195545    
Bc -> Jpsi mu nu (signal sample) /BcJpsiMuNu_020519/cgalloni-Fall18_10_2_9-MINIAODSIM_noDuplCheck-092bfc61e82f18935ea11e32077a486f/USER prod/phys03 798298    
inclusive Jpsi + X (BG sample) /BJpsiX_MuMu_270819/cgalloni-Autumn18_10_2_9_miniAOD-39a089a8e7301f392b8b059e430f83ef/USER prod/phys03 1897849    
Bc -> Jpsi tau nu (signal sample, central production) /BcToJPsiTauNu_TuneCP5_13TeV-bcvegpy2-pythia8-evtgen/RunIIAutumn18MiniAOD-102X_upgrade2018_realistic_v15-v1/MINIAODSIM/ prod/global     INVALID

  • Private signal production (with noPU) here
  • Configuration files set by Camila Galloni here
  • Central samples (requested) McM

-- GabrielRamirezSanchez - 2020-02-18

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Topic revision: r10 - 2021-05-07 - GabrielRamirezSanchez
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