RevModPhys.84.1477】Tests of the standard electroweak model at the energy frontier

Lfs and the nal result is the combination of these

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

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 LF (B)NN BDT LFS ET þ jets 6 2 0 0.7 0.8 0.9 1 10 1 0 0.2 0.4 0.6 0.8 1 Super Discriminant FIG. 47 (color online). The combined discriminant for the CDF analysis. Rev. Mod. Phys., Vol. 84, No. 4, October–December 2012 ÁÁÁ 4:70þ1::18 À0 93 3:74þ0::95 À0 79 ÁÁÁ ÁÁÁ þ0 7 2:5À0::8 þ0 8 1:6À0::7 1:8 Æ 0:6 þ0 7 2:1À0::8 þ0 9 1:5À0::8 þ2 6 4:9À2::2 Combined 5 3:94 Æ 0:88 þ0 6 2:3À0::5 a Predicted Predictedb 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 LF, CDF BNN, CDF BDT, CDF LFS, CDF MET+jets, CDF Combined, CDF [b] Combined, CDF+D0 [c] Theory1 [d] 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 Group (2009a). 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 qffiffiffiffiffiffiffiffiffiffiffiffiffi R 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...
View Full Document

This document was uploaded on 09/28/2013.

Ask a homework question - tutors are online