Measurements of properties of the Higgs-like boson in the H → ZZ(*) → 4ℓ decay channel using the ATLAS detector

• Main Author: Stahlman JM
• Format: Article
• Language: English
• Published: EDP Sciences 2014-04-01
• Series: EPJ Web of Conferences
• Online Access: http://dx.doi.org/10.1051/epjconf/20147100124

This article presents results on measurements of the signal strength, mass, and spin of the recently discovered Higgs-like boson in the H → ZZ(*) → 4ℓ decay channel using the ATLAS detector. The results are based on the combined dataset of the 2011 and 2012 LHC runs consisting of 4.6 fb−1 of ps √s = 7 TeV and 20.7 fb−1 of √s = 8 TeV proton-proton collision data. An excess of events is observed corresponding to mH = 124.3 GeV with a p0 value of 2.7 × 10−11 (6.6 standard deviations). The fit at this mass point yields a signal strength relative to the SM of 1.7−0.4+0.5 with mH = 124.3−0.5+0.6 (stat)−0.3+0.5 (syst) GeV. Tests of various spin-parity hypotheses are also presented, with the 0− and 1+ hypotheses being excluded versus the 0+ hypothesis at >97% confidence level.