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Report number	arXiv:1207.1451 ; CERN-PH-TH-2012-187 ; CERN-PH-TH-2012-187
Title	The apparent excess in the Higgs to di-photon rate at the LHC: New Physics or QCD uncertainties?
Author(s)	Baglio, J. (KIT, Karlsruhe, TP) ; Djouadi, A. (Orsay, LPT ; CERN) ; Godbole, R.M. (CERN ; Bangalore, Indian Inst. Sci.)
Publication	2012-09-17
Imprint	09 Jul 2012
Number of pages	5
Note	Comments: LaTeX, 2 figures, 9 pages LaTeX, 2 figures, 9 pages. Final version published in Physics Letters B with minor typos corrected
In:	Phys. Lett. B 716 (2012) 203-207
DOI	10.1016/j.physletb.2012.08.013
Subject category	Particle Physics - Phenomenology
Abstract	The Higgs boson with a mass $M_H \approx 126$ GeV has been observed by the ATLAS and CMS experiments at the LHC and a total significance of about five standard deviations has been reported by both the collaborations when the channels $H\to \gamma \gamma$ and $H\to ZZ \to 4\ell$ are combined. Nevertheless, while the rates in the later search channels appear to be in accord with those predicted in the Standard Model, there seems to be an excess of data in the case of the $H\to \gamma\gamma$ discovery channel. Before invoking new physics contributions to explain this excess in the di--photon Higgs rate, one should verify that standard QCD effects cannot account for it. We describe how the theoretical uncertainties in the Higgs boson cross section for the main production process at the LHC, $gg \to H$, which are known to be large, should be incorporated in practice. We further show that the discrepancy between the theoretical prediction and the measured value of the $gg \to H \to \gamma \gamma$ rate, reduces to about one standard deviation when the QCD uncertainties are taken into account.
Copyright/License	Preprint: © 2012-2025 CERN (License: CC-BY-3.0)

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