Diamonds are forever (like the Brout-Englert-Higgs mechanism)
The LHC’s jump in energy to 13 TeV in Run 2, together with the copious amount of collisions delivered over the last 12 months, has allowed the ATLAS experiment to collect a data sample that is more than equivalent to the one collected during Run 1.
The Higgs boson channels with decays into either two photons (H→γγ) or four leptons (H→ZZ→4l) offer the clearest signature. They both show a narrow resonant peak in the reconstructed invariant mass as illustrated in Figure . For an assumed Higgs boson mass value of mH=125.09 GeV, which was measured from the data collected in Run 1, the statistical significance of the observed excess over the background prediction from the combination of the H→γγ and H→ZZ→4l channels is approximately 10σ and thus well beyond the 5σ threshold for a (re-)discovery.
Figure  shows the measurement of the inclusive Higgs boson production cross section from both channels at center-of-mass-energies of 7 and 8 TeV (Run 1) as well as 13 TeV (Run 2). The measurements are compatible with Standard Model predictions at all three center-of-mass-energies.
ATLAS also measured the cross sections for the two dominant Higgs boson production modes through the fusion of either gluons (ggF) or vector bosons (VBF). These measurements could reveal deviations from the Standard Model in the way the Higgs boson couples to fermions and weak intermediate vector bosons (W,Z). Figure  shows that the simultaneous measurements of both cross sections from the H→γγ and H→ZZ→4l channels are also compatible with Standard Model expectations.
By ATLAS Collaboration, 4th August 2016