6 The Discovery of the Higgs Boson at the LHC
287
investigation of whether the properties of the new particle imply physics beyond the
SM.
6.7.3 Results from the Data Recorded Subsequent
to the Discovery
The combined results from the ATLAS and CMS experiment from Run 1 on the
Higgs boson production, decay rates and constraints on its couplings were published
in 2016 [37]. These results have been superseded by the ones presented below.
Results are presented from the most recently published papers (in journals or
submitted to the hep arXiv) from the two collaborations. The integrated luminosity
differs from one result to another and is indicated in the legends of the plots
presented.
The LHC centre of mass energy was increased from
√
s = 8 TeV to
√ s = 13 TeV
in 2015. At the higher value of
√ s the predicted cross-sections for the dominant
ggH production mode and the rare ttH production mode increased by factors of
~2.3 and ~ 3.8, respectively. This and the larger datasets from Run 2 allow a more
precise comparison of the properties of the Higgs boson with respect to those
predicted by the SM. In addition, since the discovery, the theoretical predictions
have become more accurate with the inclusion of further (higher) order corrections.
Details can be found below in the references included in the individual papers of the
two collaborations.
The two collaborations have also improved the reconstruction of physics objects
and the methods of analysis. Event categorization and machine learning methods are
deployed to study almost all the different production and decay modes. The analyses
described below divide events into multiple categories reflecting the different
Higgs boson production channels to improve the sensitivity of the measurements.
Associated production processes (WH and ZH), or the ttH production process, are
tagged by requiring the presence of additional leptons or jets. The VBF process is
tagged using distinctive kinematic properties such the presence of two jets with a
large separation in pseudorapidity and a large invariant jet-jet mass. In some cases
the kinematic characteristics of the whole event, such as large missing p T , are used
to preferentially select events e.g. arising from ZH production where the Z boson
decays to neutrinos.
6.7.3.1 The H → γγ
As the H → γ γ decay proceeds via W-boson and top-quark loops, it is especially
sensitive to the presence of any undiscovered heavy charged fermions and bosons.
Any significant deviation from the precise SM prediction for the cross section would
be indicative of new physics.
287
investigation of whether the properties of the new particle imply physics beyond the
SM.
6.7.3 Results from the Data Recorded Subsequent
to the Discovery
The combined results from the ATLAS and CMS experiment from Run 1 on the
Higgs boson production, decay rates and constraints on its couplings were published
in 2016 [37]. These results have been superseded by the ones presented below.
Results are presented from the most recently published papers (in journals or
submitted to the hep arXiv) from the two collaborations. The integrated luminosity
differs from one result to another and is indicated in the legends of the plots
presented.
The LHC centre of mass energy was increased from
√
s = 8 TeV to
√ s = 13 TeV
in 2015. At the higher value of
√ s the predicted cross-sections for the dominant
ggH production mode and the rare ttH production mode increased by factors of
~2.3 and ~ 3.8, respectively. This and the larger datasets from Run 2 allow a more
precise comparison of the properties of the Higgs boson with respect to those
predicted by the SM. In addition, since the discovery, the theoretical predictions
have become more accurate with the inclusion of further (higher) order corrections.
Details can be found below in the references included in the individual papers of the
two collaborations.
The two collaborations have also improved the reconstruction of physics objects
and the methods of analysis. Event categorization and machine learning methods are
deployed to study almost all the different production and decay modes. The analyses
described below divide events into multiple categories reflecting the different
Higgs boson production channels to improve the sensitivity of the measurements.
Associated production processes (WH and ZH), or the ttH production process, are
tagged by requiring the presence of additional leptons or jets. The VBF process is
tagged using distinctive kinematic properties such the presence of two jets with a
large separation in pseudorapidity and a large invariant jet-jet mass. In some cases
the kinematic characteristics of the whole event, such as large missing p T , are used
to preferentially select events e.g. arising from ZH production where the Z boson
decays to neutrinos.
6.7.3.1 The H → γγ
As the H → γ γ decay proceeds via W-boson and top-quark loops, it is especially
sensitive to the presence of any undiscovered heavy charged fermions and bosons.
Any significant deviation from the precise SM prediction for the cross section would
be indicative of new physics.