Speaker
Mikhail Kirsanov
(Russian Academy of Sciences (RU))
Description
Results are presented from searches for the standard model (SM) Higgs boson in proton-proton collisions at $\sqrt{s}=7$ and 8 TeV in five decay modes: $gamma \gamma$, $bb$, $\tau \tau$, $WW$, and $ZZ$. The analysed data correspond to integrated luminosities of up to 5.1 1/fb at 7 TeV and 5.3 1/fb at 8 TeV. The data exclude the existence of a SM Higgs boson in the ranges 110--122.5 and 127--600 GeV at 95\%~confidence level. An excess of events above the expected SM background is observed with a local significance of $4.9 \sigma$ around 125 GeV, which we attribute to the production of a previously unobserved particle. The evidence is strongest in the two final states with the best mass resolution: the two-photon final state and the final state with two pairs of charged leptons (electrons or muons). The combined excess in these channels alone gives a local significance of $5.0 \sigma$. An unconstrained fit to the excesses in these two final states yields a mass of $125.3~\pm 0.4~(\mathrm{stat})~\pm 0.5~(\mathrm{syst})$ GeV. Within the statistical uncertainties, the results obtained in all search channels are consistent with the expectations for a SM Higgs boson.
Author
Mikhail Kirsanov
(Russian Academy of Sciences (RU))
