Search for the standard model Higgs boson in associated WH production in the e-mu-tau and mu-mu-tau final states

This is a condensed description with plots for the analysis CMS-HIG-12-006

Abstract

A search is performed for the Higgs boson produced in association with a W boson in pp collisions at a center-of-mass energy of 7 TeV at the LHC. Final states with three leptons, including at least one tau decaying hadronically, are considered. The results are based on the full 2011 data sample recorded by the CMS experiment, corresponding to an integrated luminosity of 4.7 fb-1. The data are found to be consistent with the expected SM background. An upper limit of 6-13 times greater than the predicted value is set at 95% CL for the product of the standard model Higgs boson production cross section and decay branching fraction in the mass range 100 < M_H < 140 GeV.

Main Results

Two channels are considered in this analysis: events with an electron, a muon, and a hadronic tau decay, and events with two muons and a hadronic tau decay. To reduce the background from Drell-Yan + fake tau-jet events, the two light leptons (e/mu) are required to have the same charge. Limits are set at 95% CL using the CL_s method and the number of observed and expected events.

Table 1: Table of 95% CL observed and expected CLs limits on SM WH Production
 \begin{tabular}{|c|c|c|c|c|c|c|} \hline Mass &amp; -2$\sigma$ &amp; -1$\sigma$ &amp; Expected &amp; +1$\sigma$ &amp; +2$\sigma$ &amp; Observed\\ \hline 100 &amp; 4.5 &amp; 5.8 &amp; 8.1 &amp; 11.4 &amp; 15.8 &amp; 6.0\\ 110 &amp; 5.9 &amp; 7.6 &amp; 10.8 &amp; 15.4 &amp; 21.9 &amp; 8.0\\ 120 &amp; 5.9 &amp; 8.7 &amp; 11.7 &amp; 16.9 &amp; 23.6 &amp; 8.9\\ 130 &amp; 7.8 &amp; 11.5 &amp; 16.2 &amp; 23.3 &amp; 32.3 &amp; 12.1\\ 140 &amp; 9.1 &amp; 11.7 &amp; 16.4 &amp; 23.9 &amp; 34.1 &amp; 13.4\\ \hline \end{tabular}

Table 2: Final yields and background expectations
 \begin{tabular}{|c|c|c|} \hline Channel  &amp; $\mu\mu\tau$ &amp; $e\mu\tau$ \\ \hline Fakes &amp; $3.09 \pm 1.03$ &amp;  $5.64 \pm 1.80$  \\ WZ &amp; $2.13 \pm 0.35$ &amp;  $2.12 \pm 0.35$  \\ ZZ &amp; $0.17 \pm 0.07$ &amp;  $0.18 \pm 0.07$  \\ Triboson &amp; $0.20 \pm 0.20$ &amp;  $0.20 \pm 0.20$  \\ \hline Backgrounds &amp; $5.60 \pm 1.11$ &amp; $8.15 \pm 1.84$ \\ \hline Observed &amp; 5 &amp; 4 \\ \hline VH ($m_H = 120$~GeV) &amp; 0.40 &amp; 0.38 \\ \hline \end{tabular}

Figures from CMS-HIG-12-006

Figure Label Description
Figure 1 (left) pdf Distribution of L_T variable in the e-mu-tau channel before requiring L_T > 80 GeV
Figure 1 (right) pdf Distribution of L_T variable in the mu-mu-tau channel before requiring L_T > 80 GeV
Figure 2 (right) pdf Invariant mass of subleading lepton and hadronic tau after all selections in e-mu-tau channel
Figure 2 (left) pdf Invariant mass of subleading muon and hadronic tau after all selections in mu-mu-tau channel
Figure 3 pdf Combined 95% CL upper CLs limit on sigma/sigma_SM

Additional plots for public talks

Figure Label Description
Log version of Figure 2 (right) pdf Invariant mass of subleading lepton and hadronic tau after all selections in e-mu-tau channel
Log version of Figure 2 (left) pdf Invariant mass of subleading muon and hadronic tau after all selections in mu-mu-tau channel
Jet to electron fake rate pdf Jet to electron fake rate measured in W/Z events versus jet pT.
Jet to muon fake rate pdf Jet to muon fake rate measured in W/Z events versus jet pT.
Electron anti-iso control region pdf Observed events in the e-mu-tau electron anti-isolated control region compared to the prediction from simulation. The statistics of the QCD sample are limited, no simulated QCD events passing all selections is consistent with the data driven prediction of the QCD yield.
Electron anti-iso control region pdf Observed events in the e-mu-tau electron anti-isolated control region and the data-driven QCD yield estimate in that region.
Muon anti-iso control region pdf Observed events in the e-mu-tau muon anti-isolated control region compared to the prediction from simulation. The statistics of the QCD sample are limited, no simulated QCD events passing all selections is consistent with the data driven prediction of the QCD yield.
Muon anti-iso control region pdf Observed events in the e-mu-tau muon anti-isolated control region and the data-driven QCD yield estimate in that region.
Study of "subleading mass" pdf Figure 2 of the PAS shows the invariant masses of the subleading (lower pt) light lepton and the hadronic tau for the two channels. This observable is expected to be correlated with the invariant mass of the Higgs boson candidate. The light lepton coming from the Higgs boson decay is expected to have lower pt, as it is associated with more neutrinos. This plot shows the true visible invariant mass of the Higgs boson (green) compared to the invariant mass of the subleading lepton and hadronic tau. The "subleading mass" observable is almost identical to the true visible Higgs mass.
Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf combined.cls.pdf r1 manage 14.8 K 2012-03-01 - 12:37 EvanFriis Combined CLs limit at 95% CL
PNGpng combined.cls.png r1 manage 98.6 K 2012-03-01 - 12:49 EvanFriis  
PDFpdf electron_fakerate.pdf r1 manage 22.6 K 2012-03-05 - 12:03 EvanFriis Measured jet to electron fake rate
PNGpng electron_fakerate.png r1 manage 108.9 K 2012-03-05 - 12:03 EvanFriis  
PDFpdf emt_electron_antiiso_cr_vs_mc.pdf r1 manage 14.9 K 2012-03-05 - 12:12 EvanFriis Observed events in emutau anti-isolated electron region (and MC prediction)
PNGpng emt_electron_antiiso_cr_vs_mc.png r1 manage 62.3 K 2012-03-05 - 12:12 EvanFriis  
PDFpdf emt_muon_antiiso_cr_vs_mc.pdf r1 manage 14.7 K 2012-03-05 - 12:12 EvanFriis Observed events in emutau anti-isolated muon region (and MC prediction)
PNGpng emt_muon_antiiso_cr_vs_mc.png r1 manage 57.9 K 2012-03-05 - 12:13 EvanFriis  
PDFpdf emt_qcd_est_in_electron_antiiso_cr.pdf r1 manage 14.2 K 2012-03-05 - 12:13 EvanFriis Observed events in emutau anti-isolated electron region and data-driven QCD estimate
PNGpng emt_qcd_est_in_electron_antiiso_cr.png r1 manage 51.1 K 2012-03-05 - 12:14 EvanFriis  
PDFpdf emt_qcd_est_in_muon_antiiso_cr.pdf r1 manage 14.1 K 2012-03-05 - 12:14 EvanFriis Observed events in emutau anti-isolated muon region and data-driven QCD estimate
PNGpng emt_qcd_est_in_muon_antiiso_cr.png r1 manage 47.6 K 2012-03-05 - 12:14 EvanFriis  
PDFpdf fig1_left_emt_lt.pdf r1 manage 15.2 K 2012-03-01 - 12:32 EvanFriis Figure 1 Left (EMT LT distribution)
PNGpng fig1_left_emt_lt.png r1 manage 60.3 K 2012-03-01 - 12:50 EvanFriis  
PDFpdf fig1_right_mmt_lt.pdf r1 manage 15.3 K 2012-03-01 - 12:32 EvanFriis Figure 1 Right (MMT LT distribution)
PNGpng fig1_right_mmt_lt.png r1 manage 60.6 K 2012-03-01 - 13:45 EvanFriis  
PDFpdf fig2_final_emt_mass.pdf r1 manage 15.0 K 2012-03-01 - 12:33 EvanFriis Figure 2 (EMT "Subleading" mass)
PNGpng fig2_final_emt_mass.png r1 manage 62.9 K 2012-03-01 - 13:47 EvanFriis  
PDFpdf fig2_final_emt_mass_log.pdf r1 manage 14.9 K 2012-03-01 - 12:34 EvanFriis Log version of Figure 2 EMT mass
PNGpng fig2_final_emt_mass_log.png r1 manage 60.8 K 2012-03-01 - 13:46 EvanFriis  
PDFpdf fig2_final_mmt_mass.pdf r1 manage 15.0 K 2012-03-01 - 12:33 EvanFriis Figure 2 (MMT "Subleading" mass)
PNGpng fig2_final_mmt_mass.png r1 manage 61.2 K 2012-03-01 - 13:47 EvanFriis  
PDFpdf fig2_final_mmt_mass_log.pdf r1 manage 14.9 K 2012-03-01 - 12:34 EvanFriis Log version of Figure 2 MMT mass
PNGpng fig2_final_mmt_mass_log.png r1 manage 61.8 K 2012-03-01 - 13:47 EvanFriis  
PDFpdf mu_ewk_fakerate.pdf r1 manage 22.3 K 2012-03-05 - 12:04 EvanFriis Jet to muon fake rate measured in W and Z events
PNGpng mu_ewk_fakerate.png r1 manage 123.7 K 2012-03-05 - 12:04 EvanFriis  
PDFpdf subleading_observable.pdf r1 manage 14.4 K 2012-03-05 - 14:30 EvanFriis MC Truth study of "subleading" lepton mass
PNGpng subleading_observable.png r1 manage 72.3 K 2012-03-05 - 14:32 EvanFriis  
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Topic revision: r5 - 2012-03-10 - ChristophPaus
 
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