Measurement of sigma(ppbar->W) x BR(W->e nu) 

with electron identified by the Plug Calorimeter (1.2<|eta|<2.8): 

Blessed numbers and plots

CDF Public Note 8119

Authors: G. Chiarelli, M. Ciljak, I. Fedorko, J.E. Garcia, N. Giokaris, S. Leone, A. Sidoti, A. Staveris

Last Updated: May 5th , 2006

We present a measurement of the sigma(pp->W)xBF(W->enu)at  sqrt(s)=1.96 TeV in the forward  region  1.2 < | eta | < 2.8  using combined calorimetric and tracking information.

Candidate events have been collected by a calorimetric trigger that requests Missing Transverse Energy (MET>15 GeV) and an Electromagnetic cluster in the Plug calorimeter with Et>20 GeV. Then, candidate events are selected with the following cuts.

Event criteria



Et (transverse energy) > 20GeV
Plug electron pseudorapidity  1.2 < | eta |<2.8


MEt (missing transverse energy) > 25 GeV

Electron ID

Relative Calorimetric Isolation (Cone Radius R=0.4)<0.1

Track Matching

The extrapolation of a track with Pt > 1 GeV/c to the Plug Shower Max (PES) has to be within a distance  of  3cm of the position  of the Electromagnetic Cluster measured with the PES:

 Delta(XPES,XTrk) < 3 cm

 Delta(YPES,YTrk) < 3 cm


z0 of  electron candidate track:  | z0 | < 60 cm


Ratio between total energy of electromagnetic cluster  and total momentum of matched track:
E/P < 2.0

After analyzing  223 pb-1 of data collected in CDF Run II we measure a cross section of:
2.796 +/-0.013(stat) + 0.095 – 0.090 (syst) +/- 0.168 (lum.) nb.
The result is in agreement with previous CDF measurements in the central region and with theoretical estimates.

Event Yields, Background Summary and Overall Efficiencies:

Ratio of central-to-forward W cross section in the electron channel:

Rexp = 0.925 +- 0.033

The theoretical NLO predictions are:

RCTEQ = 0.9243 +- 0.037

RMRST01E = 0.9414 +- 0.012

Kinematical quantities blessed plots:

Transverse mass distribution of W -> e nu candidate events.


Transverse energy of electrons in W -> e nu candidate events.


Missing transverse energy in W -> e nu candidate events.


Summary of W cross section at the Tevatron

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Summary of 20 years of W and Z cross section measurements at hadron colliders.




Acceptance (from Pythia Montecarlo + detector simulation) as a function of the W rapidity (from hepg) for central (red) and forward (blue) analysis. The two curves are shown together for comparison (they are not normalized to each other).




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