Higgs Searches in ATLAS

TL;DR

This paper reports the discovery of a new boson at 126 GeV consistent with the Standard Model Higgs, based on combined analyses of multiple decay channels from ATLAS data at 7 and 8 TeV.

Contribution

It provides the first evidence and measurement of the properties of the Higgs boson using combined ATLAS data from 2011 and 2012.

Findings

Discovery of a boson at 126 GeV with 5.9 sigma significance

Measurements of the boson's couplings consistent with the Standard Model

Combined analysis of multiple decay channels enhances discovery confidence

Abstract

This talk covers the results of a search for the Standard Model Higgs boson in proton-proton collisions with the ATLAS detector at the LHC. The datasets used correspond to integrated luminosities of approximately 4.8 fb-1 collected at sqrt(s) = 7 TeV in 2011 and 5.8 fb-1 at sqrt(s) = 8 TeV in 2012. Individual searches in the channels H->ZZ(*)->4l, H->\gamma\gamma\ and H->WW(*)->e\nu\mu\nu\ in the 8 TeV data are combined with previously published results of searches for H->ZZ(*), WW(*), bb and \tau+\tau- in the 7 TeV data and results from improved analyses of the H->ZZ(*)->4l and H->\gamma\gamma\ channels in the 7 TeV data. Clear evidence for the production of a neutral boson with a measured mass of 126.0 +/- 0.4 (stat) +/- 0.4 (sys) GeV is presented. This observation, which has a significance of 5.9 standard deviations, corresponding to a background fluctuation probability of 1.7 x 10-9, is compatible with the production and decay of the Standard Model Higgs boson. First measurements of the couplings of this particle are presented and are compatible with a SM Higgs boson hypothesis.