Naslov
Search for a Standard Model Higgs boson in the decay channel H → ZZ^(*) → 4l

Autori
Amapane, N. ; ... ; Lelas, D. ; Plestina, R. ; Puljak, I. ; ...

Izvornik
CMS Analysis Note 2011/123

Vrsta, podvrsta
Ostale vrste radova, ostalo

Godina
2011

Ključne riječi
CMS; LHC; Higgs boson

Sažetak
A search for a Higgs boson in the decay channel ${;\rm H}; \rightarrow {;\rm ZZ};^{;(*)};$ with each Z boson decaying to an electron or muon pair is presented using pp collisions from the LHC at $\sqrt s$ = 7 TeV. The data analyzed correspond to an integrated luminosity of $1.66 \pm 0.07 \ ; $fb$^{;-1};$ recorded by the CMS detector in 2010 and 2011. The search covers Higgs boson mass ($m_{;\rm H};$) hypotheses of $110 < m_{;\rm H}; < 600 $GeV/c$^{;2};$ with an expected sensitivity varying between one and five times the standard model cross section at 95\% CL over most of the mass range. Twenty one events are observed, while $21.2 \pm 0.8$ events are expected from standard model background processes. Six of the events are below the kinematic threshold of two on-shell Z's ($m_{;\rm H}; < 180 $ GeV/c$^{;2};$), while $2.8\pm 0.2$ background events are expected. The events are not clustered in mass excluding interpretation as the standard model Higgs boson. The distribution of events is consistent with the expectation of standard model continuum production of ${;\rm ZZ};^{;(*)};$ pairs and the production cross section for $60 < m_{;\rm Z}; < 120 $ GeV/c$^{;2};$ is measured to be in agreement with the predicted value. Upper limits at 95\% CL on the cross section$\times$branching ratio for a Higgs boson with standard model-like decays exclude cross sections from about one to two times the expected standard model cross section for masses in the range $150 < m_{;\rm H}; < 420 $ GeV/c$^{;2};$. Reinterpreted in the context of the standard model with four fermion families a Higgs boson with a mass in the range 120-520 GeV/c$^{;2};$ is excluded at 95\% CL. This note accompanies and provides documentation for the HIG-11-015 PAS.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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