CERN Accelerating science

Preprint
Report number	arXiv:1208.1744
Title	Independent evaluation of the significance of the recent ATLAS and CMS data
Author(s)	Ranucci, Gioacchino (INFN, Milan)
Publication	2012
Imprint	09 Aug 2012
Number of pages	12
Note	Comments: 12 pages, 12 figures 12 pages, 12 figures
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LHC ; ATLAS CERN LHC ; CMS
Abstract	This note describes an independent assessment of the statistical significance of the recently released ATLAS and CMS data, about 11 fb-1 per experiment acquired in 2011 and in the first part of 2012, for what concerns the Higgs search in the two high resolution decay channels especially suited for the low mass region, i.e. the diphoton and four-lepton decay channels. Scope of this note is not to reproduce the analysis of the Collaborations: this would be impossible given the enormous complexity of the complete profile likelihood procedure used to evaluate local and global the p-values, and the huge number of nuisance parameters which are used to incorporate the numerous systematic effects. Rather, its purpose is to show the significance that an outsider can infer only on the basis of the released data and plots, used as input of a simplified profile likelihood procedure in which the only contemplated nuisance parameter is the background normalization in the diphoton channel. In practice, this note tries to address the question of the independent judgment of the significance of new data that physicists are used to perform on their own when they are shown for the first time particularly relevant results with indication of new effects, and that in the complex LHC framework is not so easily doable as in other experimental contexts.
Other source	Inspire