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

Based on nns trained in each analysis channel and at

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Unformatted text preview: , 2010c) Limit Limit Limit Limit (exp.) (obs.) (exp.) (obs.) 120 130 140 145 150 155 160 165 170 175 180 190 200 9.74 13.6 8.85 12.04 5.40 6.63 4.41 6.38 3.48 5.21 2.85 4.21 3.07 3.94 2.43 3.23 2.58 3.29 2.05 2.62 2.02 3.25 1.67 2.04 1.43 1.82 1.26 1.34 1.36 1.55 1.20 1.29 1.65 1.96 1.44 1.69 2.06 1.89 1.72 1.94 2.59 2.11 2.09 2.24 4.20 3.27 3.24 4.06 6.23 5.53 4.53 6.74 Rev. Mod. Phys., Vol. 84, No. 4, October–December 2012 Hobbs, Neubauer, and Willenbrock: Tests of the standard electroweak model at . . . 1524 Tevatron Run II Preliminary, L=2.0-5.4 fb 95% CL Limit/SM LEP Exclusion Tevatron Exclusion Expected Observed ±1σ Expected ±2σ Expected 10 -1 are a factor of 2.7 higher than the SM prediction for mH ¼ 115 GeV=c2 and production of a SM Higgs is excluded at the 95% C.L. in the region 163 < mH < 166 GeV=c2 . The results are shown in Fig. 67 expressed as a ratio of the 95% C.L. upper bound cross section divided by the SM prediction. VI. SUMMARY AND OUTLOOK 1 SM=1 November 6, 2009 100 110 120 130 140 150 160 170 180 190 200 2 mH(GeV/c ) FIG. 67 (color online). The 95% C.L. upper bounds on the Higgs production cross section divided by the predicted cross section. This result includes both published and preliminary results from CDF and D0. sections of each process (Aaltonen et al., 2009h) (see also Sec. III.E.4 for the case of SM WW ). An example NN discriminant distribution for the combination of all categories is shown in Fig. 65, where signal and background expectations for a 160 GeV=c2 Higgs boson are compared to the observed data. No significant excess of events beyond SM background expectations in the NN discriminant are observed. The 95% confidence limits on H , expressed as a ratio to the expected SM rate as a function of mH , are determined from the data. The median expected and observed upper limits on H as a function of mH are shown in Fig. 66. The expected and observed upper limits at 95% C.L. for Higgs-boson production cross section expressed as a ratio to the cross section predicted by the SM as a function of mH for the CDF and D0 searches for H ! WW ðÃÞ in Aaltonen et al. (2010c) and Abazov et al. (2010b), respectively, are shown in Table XLI. C. Combined limits Results for individual search final states are combined by the Tevatron New-Phenomena and Higgs Working Group. The combinations are updated roughly every six months to one year using the most up to date preliminary and published results. The combination is performed using a joint probability density incorporating each channel as an individual result with systematic uncertainties and their correlations included. Two algorithms are used for the combination. One is a Bayesian approach (Aaltonen et al., 2010c), and the other is a modified frequentist approach (Junk, 1999; Fisher, 2006). In both algorithms, the impact of systematic uncertainties is reduced by treating these as nuisance parameters. Results for the 95% C.L. upper bound on the Higgs production...
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