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Unformatted text preview: rements from the
Tevatron (in pb). The D0 result used Mt ¼ 170 GeV=c2 in simulations and calculation. The CDF result used Mt ¼ 175 GeV=c2 . The
predicted cross section changes by 0.1 pb for a 5 GeV=c2 change in
Mt in this region. 10 The combined discriminant for the D0 4 st ¼ s þ t 10 D0 Events 103
10 CDF 4:40þ0::99
À0 79 ME
ET þ jets
6 2 0 0.7 0.8 0.9 1 10
0 0.2 0.4 0.6 0.8 1 Super Discriminant FIG. 47 (color online). The combined discriminant for the CDF
Rev. Mod. Phys., Vol. 84, No. 4, October–December 2012 ÁÁÁ
ÁÁÁ þ0 7
1:8 Æ 0:6
4:9À2::2 Combined 5 3:94 Æ 0:88 þ0 6
2:3À0::5 a Predicted
a st ¼ 3:46 Æ 0:18 for Mt ¼ 170 GeV=c2
st ¼ 3:14 Æ 0:31 Kidonakis, 2006.
Harris et al., 2002. b Hobbs, Neubauer, and Willenbrock: Tests of the standard electroweak model at . . .
ME, D0 1511 V. HIGGS BOSON BNN, D0 A. Precision electroweak constraints ME, CDF
Combined, CDF [b]
Combined, CDF+D0 [c]
Theory2i [e] 0 1 2 3 4 5 6 7 8 9 10 σs+t (pb) FIG. 48 (color online). Ideogram of the single-top cross-section
measurements from D0 and CDF. [a] Abazov et al. (2008h);
[b] Aaltonen et al. (2008d); [c] Tevatron Electroweak Working
Group (2009a); [d] Smith and Willenbrock (1996); Harris et al.
(2002); Campbell, Ellis, and Tramontano (2004); Sullivan (2004);
Cao et al. (2005); Cao, Schwienhorst, and Yuan (2005); Frixione
et al. (2006); Kidonakis (2006); [e] Stelzer, Sullivan, and
Willenbrock (1997). network trained on the outputs of the multivariate methods.
Figure 46 shows the output of the three multivariate classiﬁers for D0, and Fig. 47 shows the same for three of the CDF
classiﬁers. The cross sections for each MV method, the
combined cross sections, and the ﬁt probabilities are given
in Table XXVI and in Fig. 48. The CDF and D0 results have
also been combined by the Tevatron Electroweak Working
The SM cross section is proportional to jVtb j2 , so the crosssection results are used to measure jVtb j. The only assumption
is that jVtb j ) jVts j, jVtd j such that there is not a signiﬁcant
contribution to the signal from initial-state s or d quarks being
transformed into top quarks via a t-channel W boson. These
results are shown in Table XXVII. The measured single-top
cross section is in good agreement with the SM prediction
with jVtb j ’ 1.
The precision of these results is limited by the statistics of
the data samples. Both experiments are expected to continue
these analyses through the end of the Tevatron running. In the
most optimistic scenario this will result in analyzed data
samples of up to 10 fbÀ1 . Assuming the results in
Table XXVII scale as 1= Ldt, the uncertainty on jVtb j
will be reduced approximately twofold.
TABLE XXVII. jVtb j values extracted from the singl...
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