Search for a Standard Model Higgs boson in the decay channel H to ZZ to lltautau

Search for the standard model Higgs boson in the H to ZZ to lltautau decay channel in pp collisions at sqrt{s}=7 TeV http://cdsweb.cern.ch/record/1424729?ln=en

Abstract

A search is reported for the standard model Higgs boson in the H to ZZ to lltautau decay mode, where l = mu or e, in proton-proton collisions at $\sqrt{s}=7$\TeV, corresponding to an integrated luminosity of 4.7\fbinv collected with the CMS detector at the LHC. No evidence is found for a significant deviation from the background expectation. An upper limit four to twelve times larger than the predicted value is set at 95\% confidence level for the product of the standard model Higgs boson production cross section and decay branching fraction in the mass range $190 < \mH < 600\GeV$.

Main Results

Ten lltautau candidates are observed in eight search channels, while $11.60 \pm 0.54\stat \pm 1.62\syst$ background events are expected.

The product of the acceptance and branching fraction for the individual lltautau-decay channels ranges between 0.01--0.02 for $\mH = 200\GeV$, and increases by a factor of three to four for $\mH = 400$--450\GeV. This behaviour is expected. The final-state leptons produced in $tau$ decays of more massive Higgs bosons have higher momenta than those from direct $\PZ \to \ell\ell$ production and the selection requirements and the lepton reconstruction become more efficient at larger $\mH$. While the cross section decreases with increasing $\mH$, the expected number of Higgs boson events selected by this analysis in 4.7\fbinv of pp collisions at 7\TeV is 1.4--1.5 in the range $200 < \mH < 400\GeV$, and decreases rapidly at higher masses.

In Figure the expected and observed upper limits at 95\% CL on the product of the Higgs boson production cross section and decay branching fraction normalized to the SM expectation are presented as a function of $\mH$. The limits are calculated with the modified frequentist construction CLs based on the shape of the lltautau invariant mass distributions by including all eight individual channels in the likelihood combination. The green and yellow bands represent the one- and two-standard-deviation variations from the expected limit. The systematic uncertainties are introduced in the form of nuisance parameters with log-normal probability density functions. The upper limit on the cross section is approximately a factor four to twelve larger than the SM Higgs boson production cross section in the range of $190 < \mH < 600\GeV$.

Figures from the paper

Figure Label Description
fig1.png pdf The four-lepton reconstructed mass summed for all $\taus$ final states. The data corresponds to an integrated luminosity of 4.7 \fbinv. The backgrounds are presented as stacked histograms. The background shapes are taken from MC simulation and normalized to the values obtained using the data-driven techniques described in the text. The expected mass distributions for the SM Higgs boson with a mass 200 or 400 GeV are also shown for comparison.
fig2new.png pdf The expected and observed 95\% CL upper limits on the product of the production cross section and decay branching ratio for a Higgs boson normalized to the SM expectation as a function of $m_{\rm H}$.

Additional public plots

Figure Label Description
fig3a.png pdf Data to MC comparison in the opposite sign control region for eett final state
fig3b.png pdf Data to MC comparison in the same sign control region for eett final state
fig3c.png pdf Data to MC comparison in the opposite sign control region for mmtt final state
fig3d.png pdf Data to MC comparison in the same sign control region for mmtt final state
fig4.png pdf Data to MC comparison for dZ variable
fig5.png pdf Data to MC comparison for the tau fake rate
fig6.png pdf Subleading Z mass in eeet final state, without cut on M_Z
11119024.png pdf event display
47105541.png pdf event display

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf 11119024.pdf r1 manage 171.5 K 2011-12-11 - 16:55 AlexanderSavin  
PNGpng 11119024.png r1 manage 115.5 K 2011-12-11 - 16:56 AlexanderSavin  
PDFpdf 47105541.pdf r1 manage 121.8 K 2011-12-11 - 16:55 AlexanderSavin  
PNGpng 47105541.png r1 manage 88.3 K 2011-12-11 - 16:56 AlexanderSavin  
PDFpdf fig1.pdf r1 manage 14.4 K 2012-05-07 - 13:40 AlexanderSavin  
PNGpng fig1.png r1 manage 9.7 K 2012-05-07 - 13:41 AlexanderSavin  
PDFpdf fig2.pdf r2 r1 manage 18.7 K 2012-05-07 - 13:41 AlexanderSavin  
PNGpng fig2.png r2 r1 manage 10.1 K 2012-05-07 - 13:41 AlexanderSavin  
PNGpng fig2new.png r1 manage 9.9 K 2011-12-12 - 17:28 AlexanderSavin  
PDFpdf fig3a.pdf r3 r2 r1 manage 15.8 K 2012-05-07 - 13:41 AlexanderSavin  
PNGpng fig3a.png r3 r2 r1 manage 9.6 K 2012-05-07 - 13:41 AlexanderSavin  
PDFpdf fig3b.pdf r3 r2 r1 manage 15.8 K 2012-05-07 - 13:42 AlexanderSavin  
PNGpng fig3b.png r3 r2 r1 manage 9.5 K 2012-05-07 - 13:42 AlexanderSavin  
PDFpdf fig3c.pdf r3 r2 r1 manage 15.8 K 2012-05-07 - 13:42 AlexanderSavin  
PNGpng fig3c.png r3 r2 r1 manage 9.6 K 2012-05-07 - 13:42 AlexanderSavin  
PDFpdf fig3d.pdf r3 r2 r1 manage 15.8 K 2012-05-07 - 13:43 AlexanderSavin  
PNGpng fig3d.png r3 r2 r1 manage 9.5 K 2012-05-07 - 13:43 AlexanderSavin  
PDFpdf fig4.pdf r3 r2 r1 manage 15.9 K 2012-05-07 - 13:43 AlexanderSavin  
PNGpng fig4.png r3 r2 r1 manage 8.5 K 2012-05-07 - 13:43 AlexanderSavin  
PDFpdf fig5.pdf r3 r2 r1 manage 18.3 K 2012-05-07 - 13:43 AlexanderSavin  
PNGpng fig5.png r3 r2 r1 manage 10.2 K 2012-05-07 - 13:44 AlexanderSavin  
PDFpdf fig6.pdf r3 r2 r1 manage 14.1 K 2012-05-07 - 13:44 AlexanderSavin  
PNGpng fig6.png r3 r2 r1 manage 8.8 K 2012-05-07 - 13:44 AlexanderSavin  
PDFpdf fig6a.pdf r1 manage 14.1 K 2011-12-11 - 17:34 AlexanderSavin  
PNGpng fig6a.png r1 manage 9.4 K 2011-12-11 - 17:34 AlexanderSavin  
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