We present a measurement of the Z boson forward-backward asymmetry of the process ppbar -> &gamma*/Z + X -> e+e- + X, in the region where the dielectron invariant mass is larger than 50 GeV/c^2. The measurement uses 4.1/fb of CDF Run II data. The method of matrix inversion is used to correct for the distortion in the measurement caused by the detector resolution and photon radiation in the final state. The measurement is compared with PYTHIA v6.216 and it agrees well with PYTHIA prediction.
|Fiducial||Track Fiduciality||1.2 < |eta| < 2.8|
|ET||> 25 GeV for CC (> 20 GeV for CP)||> 20 GeV|
||Track Z0|||<= 60 cm||<= 60 cm|
|PT||> 10 GeV||N/A|
|Ehad/Eem||<= 0.055 + 0.00045 * E||<= 0.05|
|Isolation(GeV)||<= 3 + 0.02 ET||<= 1.6 + 0.02 ET|
|E/p||<= 2.0 or PT(Track) > 50 GeV||N/A|
|Q*(delta X)||-3.0 cm < Q*(delta X) < 1.5 cm||N/A|
||delta Z|||< 3 cm||N/A|
|PEM chi2 3x3||N/A||10|
Opposite charge for CC events.
For the CP events, plug electron charge is assumed to be the opposite
to the central electron.
|Mee||> 50 GeV|
Dielectron invariant mass distribution
|Response matrix .gif|
|Pseudo experiments result. The blue points are AFB in the reconstructed level and the red points are the unfolded AFB. The band corresponds to the statistical uncertainty of 4.1/fb data. .gif|
AFB in the reconstructed level.
Only statistical errors are considered.
The measurement is compared with PYTHIA v6.216 .gif
The blue line corresponds to the statistical error.
The red line corresponds to the statistical+systematic error.
The measurement is compared with PYTHIA v6.216. .gif
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Us (Yeonsei Chung or Jiyeon Han)