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

For several mh values between 115 and 200 gevc2 is

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Unformatted text preview: ction eþ eÀ Final selection Preselection 158 Æ 13 ÁÁÁ 0:7 Æ 0:1 47:0 Æ 4:4 122 Æ 11 73:9 Æ 6:4 11:5 Æ 1:0 9:3 Æ 0:9 1:0 Æ 0:1 7:2 Æ 0:8 423 Æ 19 421 274 886 ÁÁÁ 1441 159 308 202 137 117 1370 11.2 278 620 278 277 50 þ À Final selection ÁÁÁ 373 582 2659 184 236 272 171 147 408 12.7 377 659 384 083 a) 40 ÁÁÁ 1247 Æ 37 12:0 Æ 0:7 74:6 Æ 6:8 91:5 Æ 6:5 107 Æ 9 21:5 Æ 2:0 18:0 Æ 1:8 53:8 Æ 10:3 9:0 Æ 1:0 1625 Æ 41 1613 Data Signal Bkgd. ± 1 s.d. DØ 5.4 fb-1 30 20 Events / 0.1 Z= à ! eþ eÀ Z= à ! þ À Z= à ! þ À " tt W þ jets= WW WZ ZZ Multijet Signal (mH ¼ 165 GeV) Total background Data e Æ Ç Final selection 10 0 -10 -20 -30 -40 0 0.2 0.4 0.6 0.8 1 NN Output b) DØ 5.4 fb-1 95% C.L. Limit / SM Preselection Observed Limit Expected Limit Expected ± 1 s.d. Expected ± 2 s.d. 10 1 Standard Model = 1.0 120 130 140 150 160 170 180 190 200 mH (GeV) (GeV) FIG. 64 (color online). For the D0 H ! WW ðÃÞ analysis (Abazov et al., 2010b), the (a) data after subtracting the fitted background (points) and SM signal expectation (filled histogram) as a function of the NN output for mH ¼ 165 GeV=c2 . Also shown is the Æ1 standard deviation (s.d.) band on the total background after fitting. (b) Upper limit on Higgs-boson production cross section at 95% C.L. expressed as a ratio to the SM cross section. The 1 and 2 s.d. bands around the curve corresponding to the background-only hypothesis are also shown. Hobbs, Neubauer, and Willenbrock: Tests of the standard electroweak model at . . . 1523 ∫ L = 4.8 fb mH = 160 GeV 350 300 200 150 Expected ± 1σ ± 2σ tt DY W+γ ,jet Higgs × 10 Data 250 95% C.L./σSM Events / 0.05 102 WW WZ,ZZ -1 100 Observed 10 50 0 -1 1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 Standard Model 1 Neural Network Output 110 FIG. 65 (color online). The combined distribution of NN scores for backgrounds and a MH ¼ 160 GeV=c2 Higgs boson compared to the observed data shown with statistical uncertainties for the CDF H ! WW ðÃÞ analysis. The Higgs-boson distribution is normalized to 10 times the SM expectation. From Aaltonen et al., 2010c. comparison of the NN distribution between backgroundsubtracted data and the expected signal for mH ¼ 165 GeV=c2 hypothesis. Figure 64(b) shows the expected and observed upper limits as a ratio to the expected SM cross section. Assuming mH ¼ 165 GeV=c2 , the observed (expected) upper limit at 95% C.L. on Higgs-boson production is a factor of 1.55 (1.36) times the SM cross section. In the CDF analysis (Aaltonen et al., 2010c), an integrated luminosity of 4:8 fbÀ1 is used to search for H ! WW ðÃÞ in events with either an opposite-sign (OS) or same-sign (SS) charged-lepton pair. This is an inclusive search that expands the signal acceptance by 50% for mH ¼ 160 GeV=c2 compared to searching for only the ggH production process as published previously by CDF (Aaltonen et al., 2009h). The CDF analysis uses physics objects identified as jets, electrons,...
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This document was uploaded on 09/28/2013.

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