Z+Jets Inclusive Cross Section Analysis
IFAE-Barcelona
IFAE-Barcelona


Authors

Monica D'Onofrio (donofrio@fnal.gov)

Mario Martinez (mmp@fnal.gov)

Oriol Salto (salto@fnal.gov)

CDF, FNAL,
P.0. Box 500, M.S. 318
Batavia, Illinois 60510
USA


Measurement of the Inclusive Jet Cross Section in Z+jets Production
(1fb-1 analysis)

We present preliminary results on inclusive Z+jets production (Z->ee) in p-pbar collisions at √s = 1.96 TeV using data collected with the upgraded Collider Detector at Fermilab in Run II corresponding to an integrated luminosity of 1.1 fb-1. Jets are reconstructed using the Midpoint algorithm with R=0.7. Measurements are performed as a function of jet transverse momentum and jet rapidity for jets with pTjet > 30 GeV/c and |yjet|<2.1. The measurements are corrected to the hadron level and compared to NLO pQCD predictions, the latter including additional parton-to-hadron non-pQCD contributions.

  • Public Note (under construction)


  • Blessed Results

    The measurements are performed in the kinematic range defined as:
    • Two electrons with ET > 25 GeV
    • At least one central electron: |ηe|<1
    • Second electron central or forward : |ηe|<1 or 1.2 < |ηe|<2.8
    • Z mass window: 66 < Mee < 116 GeV/c2
    • ΔR (e,jet) > 0.7
    Jets are searched for using the MidPoint algorithm with R=0.7.
    Measurements are defined for hadron level jets with pTjet > 30 GeV/c and |yjet| < 2.1.

    • Mee mass distribution gif & eps
      Measured Mee invariant mass distribution in the region 46 < Mee < 136 GeV/c2 for data compared to the SM prediction. The plot includes 20 GeV/c2 sidebands around the defined signal region.

    • Z+jets inclusive cross section as a function of pTjet gif & eps
      Measured inclusive cross section for Z+jets production as a function of pTjet compared to NLO pQCD predictions as determined using MCFM. The pQCD prediction includes an additional Chad factor that accounts for non-pQCD contributions. Systematic uncertainties on data (gif & eps) and theoretical predictions are included.

    • Z+jets inclusive cross section as a function of |yjet| gif & eps
      Measured inclusive cross section for Z+jets production as a function of |yjet| compared to NLO pQCD predictions as determined using MCFM. The pQCD prediction includes an additional Chad factor that accounts for non-pQCD contributions. Systematic uncertainties on data (gif & eps) and theoretical predictions are included.

    • Cross Section vs Inclusive Jet Multiplicity gif & eps
      Measured cross section as a function of inclusive jet multiplicity compared to NLO pQCD predictions as determined using MCFM. In the ratio plot, data and NLO theory are referred to LO predictions. Only for illustration purpose, the NLO pQCD predictions without non-pQCD corrections applied are also shown. Systematic uncertainties on data and theoretical predictions are included.

    • Jet Shapes
      Measured differential and integrated jet shapes compared to different Monte Carlo predictions with different Underlying Event settings. The measurements only include statistical uncertainties.

    • Energy Flow gif & eps
      Measured energy flow in the transverse plane for Z+jets events. Event-by-event, φ=0 is defined along the direction of the Z boson. The measurement is performed considering calorimeter towers with |y|<0.7 and compared to PYTHIA Tune A Monte Carlo prediction. The measurements only include statistical uncertainties.


            Mario Martinez (mmp@fnal.gov)