Monte Carlo Validation Overview

Partition rule is lhc-Vista
Partition cuts are:
pmin = 25 GeV
pmin leptons = 25 GeV
pmin pmiss = 25 GeV
max no. of jets = 99

leptons, photons, jets or pmiss above these thresholds
 define a final state:
 1e+1j includes:
    1e+ with pt>pmin_lepton
    1j  with pt>pmin
    any number of other objects with pt<pmin

Datasets considered

Zjets-mad-new-all

  • partitioning of final states as described above
  • "new" datasets
  • includes muons and taus

Zjets-mad-new-0j

  • sums over all jets
  • considers leptons with pt>0 GeV

Zjets-mad-new-1j

  • like "all", but allows for 0 or 1+ jets

Zjets-madgraph-all

  • an update of Zjets-madgraph including:

    • small change to jet definition to match those genJets made in production
    • separation of madgraph sample into parton-level processes
    • normalized to equal number of events

  • discrepancies are in accord with those seen in Zjets-madgraph

  • Also, several percent of the madgraph events do not have a Z0 mother in the event record

    • is this indicative of a generation problem?
    • or is it a matter of translating HepMC to genParticle
    • either way, this should be investigated and fixed

Zjets-madgraph-1j

  • partitioning lumps together all events with one or more jet
  • this is useful for checking inclusive jet quantities

Zjets-madgraph-0j

  • partitioning lumps together all eventw regardless of the number of jets

  • this is useful for checking Z0 inclusive quantities

    • see 1e+1e-1pmiss

Zjets-madgraph

  • only electrons!

  • pT_Z is softer than Pythia (which is tuned to Run2 data)

    • likely, a special tune of the intrinsic kT is needed

  • jet multiplicities are softer than Pythia reference (not expected)

    • default Pythia suffers from unshowered UE issue, as seen in 1e+1e-jj final state

Zjets-madgraph-inc

  • same but with inclusive quantities

Wjets-madgraph

  • same issues as for Zjets-madgraph

Wjets-madgraph-inc

  • same but with inclusive quantities

Phjets-madgraph

  • note: the MG sample includes both "prompt" photons and brehm photons. Currently, the Pythia "benchmark" has only the prompt photon processes, i.e. qqb->gph and qg->qph

    • the normalization difference is roughly a factor of 4-5

  • distributions to be further analyzed:

    1. in 1j1ph, pt_j and/or pt_ph
    2. in 2j1ph, the dR(ph,j) separation. This indicates that many photons are coming from back-to-back jets with a hard brehm.