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Compact Muon Solenoid
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125-GeV Higgs Boson
First results on the Higgs boson from the LHC 2015 run at 13 TeV

After the Higgs boson discovery in 2012, using the data collected in the first LHC Run (2011 and 2012) at 8 TeV centre-of-mass energy, the LHC experiments have studied many of its properties and the results have been combined across LHC experiments. CMS is now preparing to perform measurements at the higher proton-proton collision energy attained in 2015 (13 TeV) in the various Higgs boson production and decay channels.

While waiting for improved calibrations and a detailed understanding of the detector at this higher energy and a 2 year shutdown period, all analyses are prepared in a "blind" manner. This means that data are carefully studied without specifically looking at the part of the data that is expected to contains the Higgs signal events. Blind analyses are a very important ingredient in different scientific fields and are considered by many a good way to avoid experimenter's influence on the results.

Below an example is given for one of the most sensitive channels contributing to the Higgs boson discovery in 2012. The 2015 13 TeV data are shown except for the part of the data distribution around the mass of the Higgs boson (125 GeV,) which is kept blind. These data will be looked only at a next stage, when all the known possible effects that could change distributions such as these are well understood. The same is done for all other CMS Higgs analysis at this point in time.
CMS event Hgg

 $\mathrm{ H \to ZZ \to 4 \ell }$. Measured four-lepton mass per event excluding the signal region for the data.
Distribution of the four-lepton reconstructed mass m($4 \ell$) in the full mass range. The [110, 150] GeV region is blinded. Points with error bars represent the data and histograms represent expected distributions from the signal and background processes.
CMS-DPS Performance Studies: Five Main Channels and Search for Invisible Decays Twiki Page
Compact Muon Solenoid
LHC, CERN