This analysis uses events from leptonic decay of the W boson. We
require a single, well isolated high-transverse-energy lepton, large
missing transverse energy (from the neutrino), and exactly two or
three high-transverse-energy jets. Of these jets, we require at least
one to be identified as originating from a b-quark by secondary vertex
tagging. The secondary vertex tag identifies tracks associated with
the jet originating from a vertex displaced from the primary vertex.
We further require the missing transverse energy and the jets not to
be collinear for low values of missing transverse energy. This requirement
removes a large fraction of the non-W background while retaining most
of the signal.
Our major backgrounds come from W + heavy flavor jets, Wbb-bar,
Wcc-bar, and Wc+jet; mistags which are W + light quark/gluon events
that are mistakenly tagged as b-jets due to detector resolution
effects; Non-W, which are mostly multijet events in which a jet is
mistakenly identified as a lepton and jets are mismeasured, providing
a false missing transverse energy signature; and top pair production
events in which one lepton or two jets are lost due to detector acceptance.
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