One of the four known forces in nature is the weak force, which
provides the mechanism for nuclear fusion in stars and
radioactive decays of heavier elements. The particle
carriers of the weak force are W and Z bosons. These
particles are heavy and short-lived, presumably due to their
interaction with the Higgs boson field, although the Higgs
itself has yet to be observed directly.
Even without direct observation, properties of the Higgs
boson can be constrained within the Standard Model
of Particles and Interactions,
which predicts its existence. Precision measurements
involving W and Z bosons improve these constraints. The most
precise electroweak measurements come from large, clean
samples of boson decays collected at high-energy electron-positron
colliders. However, the larger samples currently being
collected by the CDF and DZero experiments will improve these
Using the first 72 pb-1 of data collected in Run II, CDF has
measured the inclusive cross sections for W and Z boson
production in decay channels involving electrons and muons.
The technical challenge is to control every detail of these
analyses in order to keep systematic errors small. The CDF
team has devised new techniques that lead to substantial
improvements over previous measurements.
Of interest is the relative production rate (R) of W and Z
bosons in Tevatron collisions. CDF reports a value of
R = 10.93 +/- 0.15(stat) +/- 0.14(syst), precise to 2%.
Based on this measurement, a number of fundamental
electroweak parameters can be extracted, including an
indirect measurement of the total decay width of the W
boson, Gamma_W = 2072 +/- 40 MeV, slightly more precise than
the current world average, and consistent with theoretical
The future of these measurement is bright. Similar results
are expected from DZero in the near future, which can be
combined with those reported here to further reduce
measurement uncertainties. In addition, both collaborations
have already collected and continue to collect even larger
data samples which will lead to future improvements over the
course of Run II.