Electroweak Physics with CDF Page: 1 of 3
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FERMILAB-Conf-03/335-E October 2003
Electroweak Physics with CDF
Antonio Sidoti"
(Representing the CDF Collaboration)
Istituto Nazionale Fisica Nucleare Sezione Pisa-Dipartimento Fisica University Pisa
Received: date / Revised version: date
Abstract. The CDF experiment at the Tevatron has used pp collisions at f = 1.96 TeV to perform
electroweak physics measurements. A program of precision electroweak tests of SM started measuring W
and Z bosons cross section using different leptonic final states, evaluating dielectron Forward-Backward
Asymmetry AFB and di-boson cross section production.
PACS. 13.38.Be Decays of W bosons - 13.38.Dg Decays of Z bosons1 Introduction
The Collider Detector at Fermilab (CDF) is a general pur-
pose detector located in one of the interaction regions at
the Tevatron collider. pp collisions at the Tevatron reach
an energy in the center of mass of fi = 1.96 TeV. We are
reporting here the electroweak physics measurements per-
formed using the first physics-quality data of RunII taken
from March 2002 to January 2003.
2 W and Z Cross Sections
W and Z bosons are produced by qq annihilation. Due
to the large QCD background, decay channels of bosons
involving quarks are difficult to identify; therefore Wand
Z bosons are identified through their leptonic decays.
2.1 Measuring W Cross Section
The signature for a leptonic W boson decay is a high mo-
mentum isolated lepton with missing transverse energy
accounting for the undetected neutrino.
W -+ ev candidates are collected with a trigger se-
lecting high-ET central electron candidates; after requir-
ing one tight electron with ET > 25 GeV matched to a
track with PT > 10 GeV/c and missing transverse energy
_FT > 25 GeV, 38628 events are left in data. The trans-
verse mass distribution of the candidate events is reported
in Fig.1. Background from QCD dijets is estimated from
data assuming that its distribution is flat with respect to
the missing transverse energy. Background contamination
from other electroweak processes like W -+ jv, Z -3 ee
and W -+ rv is estimated from MC events after a detailed
simulation through our detector.
a Present address: INFN Pisa Via F. Buonarroti 2 Pisa I-
56100 Italy antonio.sidotiPpi.infn.it300
20
uj 2000
10
10040
6O s0 10
Mr. GeV/cl120 140
Fig. 1. Transverse Mass distribution of W -+ ev events col-
lected by the CDF experiment
W -+ pv candidates are collected by a high-PT muon
trigger. After requiring an isolated muon with PT > 20
GeV/c and YT > 20 GeV, 21599 W candidates remain.
The main background contamination comes from Z - p,
W - Tv, cosmic rays and dijet QCD events.
Specific triggers for selecting a sample enriched with T
events decaying into hadrons have been designed for RunII
[1]. Events with gT > 25 GeV and with the topology of
the T decaying hadronically are selected at trigger level.
W - ev events are explicitly removed. 2345 events pass
the selection with an estimated background mainly from
QCD of 612 + 61 events. Using the removed W - ev
events collected in the same data sample, the ratio of the
electroweak coupling constant has been measured:gr/ge = 0.99 0.04(stat.) + 0.07(syst.),
(1)
consistent with SM expectations.
I CDF Run i Preliminary, 72pb -
- DATA
Osum
W-ev MC
Z-aee MC
- W- MC
0F Q CD
a
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Sidoti, A. Electroweak Physics with CDF, article, November 3, 2003; Batavia, Illinois. (https://digital.library.unt.edu/ark:/67531/metadc737380/m1/1/: accessed April 23, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.